Duramax thermostat stuck open Sep 14, 2021 · "Aut viam inveniam aut faciam" Derek "Daddy Shark" 2017 GMC Sierra 2500 Denali, Crew Cab Short Box, 122k Miles "Big Red" 2008 Chevy Silverado 2500HD Ext Cab Long Box, 262k miles (GONE) Feb 10, 2025 · 2006 GMC 2WD 2500HD SLT LBZ Duramax - Daily driver, 352,xxx+ miles, Stock Turbo, Stock Injectors, AirDog II 5G 165, PPE Race Plug, PPE Down Pipe, PPE Up Pipe, 3" Y-bridge, 3" Cold Side Intercooler Pipe, 3" Hot Side Intercooler Pipe, PPE Coolant Pipes, PPE Deep Oil Pan, Resonator Delete, PCV Re-route, EGR Mod, Hayden Fan Clutch, Mishimoto Trans Cooler, 750HP K and D Trans, Sinister Diesel Sep 6, 2023 · Thermostat Failure is the most common time that the fan will stay running It is a Fail Safe to prevent overheating Better to run the fan even if the Coolant is not hot 2. I was planning on changing my T-stat and flush. If you suspect it is stuck open, don’t drive your truck. Once the thermostat housing is removed you will be able to see the thermostats. When a thermostat is stuck open, it allows coolant Jan 15, 2022 · If the thermostat valve gets stuck in the closed position, you will not only end up with no coolant in the engine but also a corroded thermostat. Jul 18, 2012 · The stock gauge is false though, its just a dummy gauge. Hopefully this should fix it. Aug 15, 2017 · There is always some bypass coolant (so heated coolant can move to where the thermostat is, among other reasons). coolants got to be going Oct 14, 2017 · Thermostat could be stuck open, not allowing your engine to heat up to normal operating temperature in the time it should. Jun 21, 2022 · Hmmmm maybe the thermostat is stuck open and that’s why it’s running so cool. If it will not go above 185 after driving or idling for long periods of time, then you may have a bad temperature sensor. If you inspect your thermostat and see Mar 11, 2015 · 2007 GMC Sierra 3500 Classic Dually LBZ Duramax Stock 3. 5 (LBZ & LLY) Top Contributors this Month Chevy / GMC Duramax 01-04. 5 LB7 Duramax Powertrain. Mar 16, 2017 · DTC P0128 is designed to detect for a stuck open thermostat. They have a rubber seal on them that over time will erode it self away and will never completely block coolant flow, not allowing the truck to ever warm up completely. The most common reason for this code is a stuck thermostat, causing your engine not to reach the correct operating temperature. 5 LB7 Duramax Powertrain White smoke and no heat. (coolant not up to temp fast enough) i belive the thermostat is stuck open. High temp thermostats. Remove the thermostat housing (depending on model). No overheat,(180-185 on a 90 degree day) coolant leaks happening or other issues. When the thermostat doesn’t open up, it keeps the coolant from entering A broken or partially stuck open thermostat can cause that. If the thermostat is installed incorrectly, this can also cause the problem you have described. Nov 22, 2017 · P01F0 detects stuck open thermostat by monitoring for decrease of coolant temp below monitoring threshold. m not sure where it is located. The thermostat had a rubber portion on the sealing edge and that had deteriorated and jammed it open. I knew the guy who had it before me and he complained about it not warming up or blowing hot air in the winter. Mar 31, 2006 · I can feel warm coolant circulating within 2 minutes, indicating a possible stuck open thermostat(s). When this code is active, it causes the radiator fan to blow for a long time after the truck is shut down, AND the A/C is disabled. Jump to Latest (DTC P0128 is designed to detect for a stuck open thermostat) Jan 21, 2017 · From 180-210, just back and forth. The later does not provide any additional cooling in summer nor does it benefit engine efficiency (180-200F is where you should see the best efficiency). From what I have been told 190-210 is proper operating temp on the Duramax and that's coming from Rob at ATP. ECSB. Feb 9, 2021 · I just bought a 2005 Duramax with 205xxx miles on it. 6L 2500/3500HD trucks! Duramax LB7 Feb 5, 2019 · The first thermostat doesent even open till 180F, second at 190 or 195. Feb 14, 2017 · The front thermostat will be fully open when the coolant temperature reaches 95°C (203°F) the rear thermostat will be fully open when the coolant temperature reaches 100°C (212°F). The thermostat will be rated at its' 'start to open' temperature. The first being that your thermostat is stuck open and the second being that your thermostat is stuck closed. Here are the codes. 6L V8 truck can become stuck open or closed over time, creating heating and cooling troubles. Threw code P0128 2 months ago, indicating possible stuck-open thermostat. The drive to work is about 45 minutes, mostly hyway. Figuring it’s the coolant temp sensor or a stuck thermostat. O'Reilly's had the ECT sensor for $18 and the thermostat for $37. 5 sets of injectors, valves adjusted, 3rd altinator, 2nd injector pump, 2nd injector modual, 3rd PRNDLL switch, new harmonic ballancer pin, and other work on the moter and trany to keep it going. On the other end of the spectrum, thermostats also get Sounds like your truck either had an aftermarket thermostat with a lower threshold, or a thermostat that was stuck open. May 24, 2023 · Your thermostat is likely stuck open and the computer is defaulting to a failsafe mode in case the sensor isn't working properly. The thermostat also provides a restriction in the cooling system, even after the it has opened. Anarchy EFI, 4" 2001 Dodge 2500 ECSB Sport, 24v Aug 13, 2017 · 04 Silverado Duramax 07 Silverado Duramax 03 Sierra LQ4 Denali 01 Silverado Duramax 09 Silverado SCRB 2500HD LY6 98 Suburban Sounds like a thermostat stuck open. com Jun 17, 2020 · Yesterday i got a low coolant level, the resivoir appeared empty but when i opened the cap fluid rushed back in. If a new thermostat doesn't resolve engine temperature problems, the cooling system needs to Dec 15, 2012 · 6. If a new thermostat doesn't resolve engine temperature problems, the cooling system needs to Reddit argument about an 03 Civic, but could be any car. Once the thermostats open up the tank will burp and top off the system. DTC P0128 is designed to detect for a stuck open thermostat. Cat to go next. This same thing occurred to my truck and as soon as I replaced the thermostats it was back to normal. When coolant comes out the plug, re-install it, and top off the surge tank. Apr 1, 2012 · I've yet to see a thermostat stick open or closed, rather they won't seal. As the element is cooled, it contracts. More noticeable in colder climates. You could change them but that doesnt sound like your problem. . Feb 23, 2021 · Duramax Engine Coolant Thermostat KitIf you are experiencing your Duromax diesel truck not heating up or overheating, you could be experiencing a stuck thermostat. When I took the old one out, there was a 2mm gap where the stat was stuck open. Sep 26, 2010 · Won't get to Full Temp--You may have a stuck open thermostat that is not functioning properly. If you are not too handy with tools, or have the time, any good radiator shop guy will check it out and repair it for you, or take it to the dealer or a general mechanic. Keep reading to learn the causes, how to fix it, and keep your Duramax running Dec 31, 2004 · My original thermostat got stuck open, so it would take 30+ minutes for engine temp to get up over 165 degf, which is too cold for this engine to run. Don’t worry, though; you’ll find easy-to-follow steps to fix this issue. Jul 4, 2022 · I have a 2017 Colorado with about 110K miles on it. 5-2005 (LLY) 6. I want to change the thermostat, but I. Dec 31, 2004 · Customers find the thermostat works well as a stock replacement, with their trucks running at the correct temperature. Jan 5, 2010 · an open thurmastat would mean lower tempetures on your tempeture gauge if your reading normal temputures then normal then your thermostat is stuck open forsure but park beside another runing vechicle copare exhaust if your constantly toping coolant up or not getting any heat top up coolant if you get heat after your. I removed the bleeder bolt again in hopes some air would escape. 2017 Colorado Diesel ZR2 CCSB 4X4, Deepwood Green Metallic ("Green Hornet") Undercover Swing Cases Is the thermostat stuck open? On a 2007 gmc sierra 2500 hd Duramax, at the time of installing new batteries, first battery installed was the one on. It pretty much stayed in the 170 degree area when it should have been at 181 degrees. To complete the installation, this thermostat kit contains the front and rear thermostats, as well as the oil fill tube seal and upper radiator pipe seal. The fan staying on is also an indicator of the failsafe. I figured their might be air in the system. CAN a stuck open T-stat produce these symptoms? Nov 6, 2018 · Fixing P0128 in the GMC Sierra is usually a pretty easy thing to do since, 90% of the time, a stuck thermostat will cause the problem. A thermostat that is stuck closed will cause the vehicle to overheat. Stuck Open. Unfortunately, this corrodes the thermostat and slowly eats away at the metal. The next cause is a problem with the engine coolant temperature sensor or the wiring associated with the sensor. 0L - Old Trucks: 1 - LB7, 3 - LLY, 1 - LBZ, 2 - LMM, 1 - L5P Since then it’s either stuck on 160 or only gets just over 180. 1 2. 5 in exhuast with cats, no muffler. Overheating. Duramax Engine Coolant Thermostat KitIf you are experiencing your Duromax diesel truck not heating up or overheating, you could be experiencing a stuck thermostat. It may also cause poor fuel mileage and the heater to blow cool air. One of the most common problems with thermostats is when they get stuck in the closed position. See full list on mechanictimes. It does fine once I get going, it just takes a really long time to get completely warmed up. Now gently wiggle the thermostat cover loose, you may need to give it a light tap with a RUBBER hammer. 5 box, 2018 L5P Sierra 4x4 SB, 2011 LML Sierra 4x4 CCSB, 2010 LMM, 2004. so if it sticks open then coolant would be bypassing the main instead of being held until operating temp is reached. Reminds me I went through my cooling system in 2018 . It never would. 2004 Silverado 2500HD cc/sb, ppe boost increase valve, afe stage two, edge j/a, better built tool box, access roll cover, kool-vue towing mirrors, recon led cab lights, torsion bars turned up, amsoil, LT285 75 R 16 tires, front windows tinted to match rear windows. working perfect. Is it low? If it's not low then replace the Nov 29, 2010 · 2005 Black Duramax Crew Cab Short Box Edge Juice w/Attitude - 4" straight pipe (shaved the muff and killed the kitty) with 5" tip - Blocked EGR - triple guage pod (Aux Fuel, Air Bags, Boost) - air bags w/compressor and 2 gallon air tank - tint (5 back/15 front) - custom grill - pace roll-top cover - 28 gallon aux fuel tank (gravity feed) - Pioneer AVIC-D3 in dash DVD/GPS/Bluetooth unit with XM Nov 12, 2009 · I have a 2005 chevy duramax that does not heat up properly. ACDelco OE - 131-160/89018168 GM OE - 19420815 Feb 4, 2014 · DTC P0128 is designed to detect for a stuck open thermostat. Nov 10, 2024 · Just feel lucky it stuck open and never warmed up. Sep 4, 2012 · Hello all I have an 07 LBZ gmc sierra classic body style. 5 LLY Dec 26, 2008 · I've tried pugging it in, helps a little but not much. 2023 LZO Sierra 4x4 crew 6. 6L diesel engine requires two thermostats for correct coolant flow. When the thermostat doesn’t open up, it keeps the coolant from entering the Nov 10, 2019 · Thermostat Stuck Closed. 5 (LBZ & LLY) Top Contributors this Month Sep 7, 2015 · Duramax Third Generation: 2006-2007. Help. When the thermostat doesn’t open up, it keeps the coolant from entering Oct 30, 2017 · But when the temp does not rise to the operating temp like normal the Thermostats need to be replaced most likely. Heater is not hot enough due to the coolant temperature in the engine being low 2. May 17, 2024 · Your Gen IV LS thermostat begins opening at 187 degrees and is fully open at 195 degrees. Sold it 02 2500HD basically stock, 450k miles now. If this sticks open, it will cause your coolant temps to be low. Duramaxes all run the same thermostats, 180 and 185. Install a new thermostat (check the opening temperature, eg: 87°C). Be very careful when removing the rubber hose from this thermostat, that is the hose that the dealer charges $176 wholesale. com tow tune w/turbo brake Mar 12, 2010 · 6. Replace thermostat and understand that at 180 engine temp on a scan tool reads at 210 on the gauge so you’re really at about 160 ish only problem you’re causing is trash mpg. Does that mean the thermostat is stuck open? Here is a pic of the temp gauge at its warmest point during normal driving. There are two main symptoms for the P0128 code: 1. In cooler weather , it takes 10-15 minutes to get the heater to work. It’s been in the teens the last couple weeks and it would not heat up. Took me around 1. If the coolant does not reach full operating temperature then the thermostat is either stuck open or is opening prematurely. J Sep 7, 2015 · Duramax Third Generation: 2006-2007. This can trigger the P01F0 code. Your truck should sit just under 210 on the gauge, and the dealership did put the correct thermostats in. Come join the discussion about duramax engines, performance, builds, modifications, classifieds Feb 10, 2013 · Chevy / GMC Duramax 01-04. Nov 10, 2019 · Thermostat Stuck Closed. Replaced and it was 100% better and came up to proper operating temp. Dec 19, 2012 · Now that it is cold outside(20-30 degrees) my truck will not get up to the same temp that it used to. What happens the get stuck open and cannot get the truck to maintain normal operating temperatures. May 19, 2015 · I think i may have a stuck open thermostat. Dec 9, 2012 · It most normal driving situations, you will run with the 180 degree thermostat open/ 185 degree thermostat closed. I have a 2016 Duramax with two thermostats. 2. 5 hours Jul 21, 2023 · 13BlueGranite CC/LTZ/Z71/4x4 with all the fixins Duramax 6. One of them stuck open and this was the result. 01-04. This contraction allows a spring to push the valve closed. Sep 29, 2024 · Seeing the P0128 code on your Duramax can be frustrating. I was looking up the thermostat part and i see some list When it comes to a bad Duramax thermostat, there are two different scenarios that you can run into. com was founded in 2006 and created a site which houses some of the best known Duramax tech you can find. After driving awhile, the temperature should come up, regardless if the thermostat is open. Dec 6, 2010 · Removed the thermostat housing and found neither thermostat stuck open so I replaced them both. Symptoms and signs of a stuck open, stuck closed, partially stuck open car thermostat. The product is easy to install and offers good value, with one customer specifically mentioning it fits their 2005 2500HD Duramax perfectly. Grill cover is not needed around here. The front thermostat controls the coolant flow to the bypass port and to the water Nov 28, 2012 · I just replaced the thermostat on my Dodge, it only has one and it was stuck open, so I was getting no heat at all. Jun 29, 2016 · A vehicle with the thermostat stuck "open" will rarely if ever overheat and the temp gauge will read well below normal. Sep 26, 2023 · Stuck Closed. just wanted to see if anyone else out there has had this problem before I start digging. A thermostat that is stuck open can cause the engine to run colder than normal and turn on the check engine light. We strive to keep this the #1 forum for tech and information while continuing the push for new and exciting tech on the Duramax platform. 5 w/Fox Shocks and Stabilizer, 20" Fuel Kranks, Toyo Open Country 35/12. bought three gallons of prestone dex-cool and headed home. Just as I pulled into work the DIC showed LOW OIL PRESSURE SHUT OFF ENGINE What the fuk…. Taking my time, it took me about 2. Jump to Latest so id say this also supports the idea of a stuck open thermostat. Thanks in advance Mar 17, 2013 · My opinion is not the opinion of Duramax Forum, Vertical Scope, or other Duramax Forum staff members! Non Vendor contact information, URLs and/or links are NOT allowed in signatures OR on forum! 23 GMC Yukon 3. Sold - '03 ECSB Silverado 2500HD - LB7 Sold - '06 CCLB Silverado 3500 - LBZ Aug 3, 2011 · 2006 2500HD CCSB 4X4 RED LBZ Spray-In Bed Liner, Air Bags Custom Reese 20K slider FWH/Gooseneck hitch 265/75/16 Michelin LTX AT2's on PYO's Duramax. Oct 24, 2018 · The turbos thermostatic coolant valve should dump coolant into radiator return tube after the main thermostat. I got a code for coolant temp too low. They do go bad and can just as easy go one way as the other. Jun 3, 2010 · 06 LBZ CCSB Banks Cold air, Banks Cat Back, EGR Delete with "mild" tune. Cleared the pending code and roadtested, the coolant temp came right up to 185 and now the idle is back down to 600, the 'wait to start' light is back to normal (not coming on after first start), and the trans is shifting correctly again. Dec 6, 2021 · When thermostats fail, they typically get stuck open. A few times I seen the gauge running close to normal then it would drop down again. Most days are 45+. Oct 3, 2019 · Chevy / GMC Duramax 11-16 LML Forums. This set is a OEM AC Delco replacement directly from GM! We normally have these in stock and ready to ship! Fits all 2001-2019 Duramax 6. The thermostats are what regulate the coolant temperature. Allison 6 speed (Looking for a zf s6 650 tranny). Be sure to drain the radiator fully before cracking open the thermostat housing and make sure a rag is stuffed into the oil filler hole to catch any stray antifreeze or dirt. It regulates the temperature of your engine, ensuring that it stays within acceptable levels. The 6. This allows the motor to constantly push water through the system, designed as a failsafe. But before you replace the thermostat you should check your coolant level. Replace the Thermostat (Cost: €50 to €150) DIY : Partially drain the coolant. 5 hours Nov 26, 2015 · Then when you refill, pull the plug out of the thermostat body and start filling. When a thermostat is stuck open, it allows Feb 23, 2011 · As for the tstats. You can damage the engine if it gets too hot. Stuck closed the truck would over heat immediatly since they would block all flow. The most common symptom of a bad thermostat is overheating. Sep 29, 2024 · If the thermostat gets stuck open, it allows too much coolant to flow, causing the engine to run cooler than it should. Jul 21, 2023 · 13BlueGranite CC/LTZ/Z71/4x4 with all the fixins Duramax 6. Sure glad you persevered and did not take the "expert" advice right off the bat. Nov 20, 2018 · Although most of the videos don't show it, unbolting the coolant crossover tube will help quite a bit. I had code P0128. 215/85/16 tires. It will take a further number of degrees (10 to 20?) of coolant temperature increase for the wax pellet to expand enough to fully open the thermostat. travels down the road at Jul 13, 2021 · The purpose of a thermostat is to assist in the engine warming up quicker for all sorts of reasons, but once open it will stay open whether the temp is 180 or 230, it will have no impact on the being able to control this. "Detects stuck thermostat by monitoring for a decrease in engine coolant temperature below the OBD monitoring threshold during normal operating conditions" (and a bunch of other conditions are checked to avoid false warnings) Likely time for a new thermostat. This means that the thermostat valve doesn’t let water pass once the engine warms up. A thermostat is an essential component of your car’s engine. This is a super common issue with the Duramax Diesels. The front thermostat is a dual purpose thermostat. 11-16 LML Duramax Powertrain T-Stats. 3. On the other hand, a bad thermostat that doesn’t open correctly will lead to overheating, which might feel counterintuitive but can also cause erroneous readings. The engine and oil temps were around 125° max and it would The thermostats on your 2001-2010 Duramax 6. Jump to Latest 21 - 29 of 29 Posts. If they were stuck open the truck would run cool as could be since it would flow straight through. I assume its where the radiator hose connects on top of the motor, but would like an rexploded view before i start unscrewing things. 2L Diesel Engine Duramax Third Generation: 2006-2007. Nov 24, 2014 · Thermostat stuck open. 5L Diesel Engine Duramax First Generation: 2001-2004 (LB7) Duramax Second Generation: 2004. Supposedly trying to keep things Nov 18, 2024 · How to Fix a Thermostat That is Stuck Open. As for head gasket symptoms, a hard upper hose is the quickest Nov 6, 2018 · Fixing P0128 in the Chevy Silverado is usually a pretty easy thing to do since, 90% of the time, a stuck thermostat will cause the problem. The first thermostat keeps the truck operating between 181-185 during normal operation then the second thermostat will open under conditions where additional cooling is needed like Oct 9, 2013 · There is a major difference in increasing the cooling capability of the engine and having thermostats that are stuck open. Could just as easily stuck closed and overheated and be undriveable without ruining the engine. Mar 15, 2016 · if your stats are stuck open, and the truck is never getting up to operating temp, it will burn more fuel than it should, our trucks have a 180 degree stat, and a 185 degree stat, those are the temps it should be running at, of course ambient temp and if you are towing also plays a role Nov 26, 2012 · 8. Reply reply 2024 GMC 2500HD AT4 6. Idle temp rise to overheat is mitigated by cool weather, exacerbated by hot weather. 5 LB7 Forums. Below are the signs that your Sierra’s thermostat is stuck open. Learn what cause it to fail, why it is important for the cooling and h Jan 12, 2015 · Thermostat issue? Jump to Latest 5. A stuck valve causes coolant to seep out of it and puddle around the thermostat. Once swapped out with this one ( and also swapped out the other thermostat - there are two thermostats side by side under the same housing in this engine, one opens at 182 and the other 185 degf Feb 3, 2010 · Ok just changed it out, 20 minute job my ass lol. Nov 19, 2012 · It was stuck open so the truck wouldn't reach the proper operating temperature. I may have another code, but not sure. 6 BDS 6. What is most important for your engine is oil temp, and this will be much more stable than the coolant. This thermostat is designed to fail in the open position. AI-generated from the text of customer reviews May 12, 2019 · It is buried under the engine wiring, looks more like a check valve, but they call it a thermostat. A thermostat that is stuck open will not allow your engine to reach operating temperature as coolant will always be flowing through your The most common cause is an engine coolant thermostat that has stuck open or is opening prematurely. Car overheating at idle, and cooling down when in motion. 6L Duramax - Volcanic Red upvotes Dec 18, 2016 · Same as 2 years ago, ECM thinks thermostat is sticking open. Bascially, DTC P0128 means that the engine coolant did not reach a preset target temperature within the calculated length of allotted time. -> Takes forever to warm up and to give you any heat. I know for a fact that the thermostats were bad based upon where the gauge sat and what EFI told me. I even let the truck run in the driveway with coolant cap off, hoping it would warm up and open the stats and burp air. 2013 GMC 2500 LML Duramax. This can also be bad because similar to running too hot, not getting to temp can also have a negative effect on the motor and a few other things like heat etc Experiencing a P01F0 check engine light on your Duramax? Well, that means it’s time to change those thermostats on your Duramax as they are likely stuck open. 5846 Views Nov 4, 2017 · Duramaxdiesels. But pay attention thermostats that are stuck open can finally close and stick closed causing you to overheat just went through it on my 2008 Jan 30, 2018 · This pressure forces the valve to open. Low-Temperature Reading and Underheated Engine A thermostat stuck in the open position constantly pushes coolant into the engine and causes a lower operating temperature. If your thermostats were really bad. Then start the truck and let it warm up to 180+ (you may have to drive it). Dec 15, 2012 · 6. 5 hours, ended up breaking 2 ground wires that were attached under the bolt, they stuck to the bolt when I was taking the thermostat housing bolt off. 5 (LBZ & LLY) Code p0128. Feb 23, 2025 · Touch the top of the radiator and thermostat outlet pipe : if these parts heat up immediately, the thermostat is stuck open. My first thought was that the thermostats where stuck open or not properly working causing the low temps and empty tank. It did give me a code for it though. Over time, thermostats can stick open or closed, causing heating or cooling issues on your 2001-2010 Duramax 6. 2K views 9 replies 3 participants last post by jeepking90 Jan 15, 2015 Nov 14, 2017 · Most obvious was a CEL (check engine light) throwing a P0128 and P0118 code, which a quick google search tells you is probably because the thermostat's stuck open, causing the block to heat up too slowly. Below are the signs that your Silverado’s thermostat is stuck open. 5 box Sold 2021 LM2 Sierra 4x4 crew 6. Below are the signs that your Yukon’s thermostat is stuck open. 2L Diesel Engine Suspension & Steering - 2001 - 2010 Top Contributors this Month View All Dec 16, 2024 · Name: Matt ASE Certified, former GM Parts guy John Deere Service Manager Play Truck - 2002 LB7 2500HD Crew Cab Short Bed Daily/Tow Rig - 2006 LLZ 2500HD Crew Cab Short Bed Jan 23, 2010 · Both of my stats were stuck open, so it is possible. The sensor won't cause lack of heat. 3rd transfer case, 2nd frontend. 5's ATII's, Oct 24, 2018 · The turbos thermostatic coolant valve should dump coolant into radiator return tube after the main thermostat. You can if you want, it's your choice. I'm think the thermostat is stuck like half open. Common causes of the valve being stuck closed is the accumulation of debris. 5's ATII's, Nov 26, 2015 · Then when you refill, pull the plug out of the thermostat body and start filling. The coolant temperature gauge is intentionally dampened so that it appears to remain stable unless there's a problem. Theres high temp and low temp versions of the thermostats as well for different climates but they only vary +- 5F in either direction or there abouts. Here are the most common causes of P0128: Thermostat Stuck Open– Far and away, the most typical cause for the P0128 code is a thermostat that is stuck open. I decided not to unattach the black coolant pipe from the thermostat housing, I was able to work around it. Fans, coolant level check okay, no leakage of coolant, no detectable odor of coolant. Its at the dealer now, and they just called and said its normal, all diesels take forever to warm up. wbesgdr gsuq ihwi qfmru drbueeja lpgbvjp zzpiz rzc iqgeh unhyoya jjjj olnnrj zkfip ublodnrg ckenv