A stuck open thermostat will cause overheating? Really? The ONLY purpose for a thermostat in a water-cooled, internal combustion engine like in a DII is to regulate the MINIMUM operating temp. It blocks or restricts coolant temp until its specified temp is reached. IT DOES NOTHING to manage temps above its operating range! Two people weighing in on one thread with completely bass-ackward opinions. Sheesh! This isn't rocket science!
Not over heating but running a little hot.
- Thread starter malonso123
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A stuck open thermostat will cause overheating? Really? The ONLY purpose for a thermostat in a water-cooled, internal combustion engine like in a DII is to regulate the MINIMUM operating temp. It blocks or restricts coolant temp until its specified temp is reached. IT DOES NOTHING to manage temps above its operating range! Two people weighing in on one thread with completely bass-ackward opinions. Sheesh! This isn't rocket science!
Yes. A removed thermostat will cause overheating. A stuck open t stat will probably have a restricted flow engineered into it. So the complaint would be no heat.
And I'm talking about standard GM V8 with the stat where it's supposed to be. Pretty sure I said I would believe pinky toe about modifying a Bosch t stat.
My suggestion was not an opinion, I've experienced the overheat condition on a couple occasions but alas it sounds like you have the all answers so I'll sit back and learn.
New 180 thermostat, new radiator - I'm going to assume only some small air bubbles remain, if any.
Just took a quick drive this A.M. with the following results. Don't know if that's the Goldilocks temp range or too hi, but this is the reading from my BlueDriver App.
Ambient Temp, 65 ish
Town Driving@35-45 - 199F
Freeway speed 65&70 - 194F -196 F
Idle at stop light for 30-45 sec - 203+-
Just took a quick drive this A.M. with the following results. Don't know if that's the Goldilocks temp range or too hi, but this is the reading from my BlueDriver App.
Ambient Temp, 65 ish
Town Driving@35-45 - 199F
Freeway speed 65&70 - 194F -196 F
Idle at stop light for 30-45 sec - 203+-
Hey pinktoe69, I modified it and was going well holding at 167 then started to creep up, hoses pressurized and reached 240. also got misfire on cyl 2 and also random misfire code. what are your thoughts? I think my misfires are from code P0441 which Evap incorrect purge. getting a new purge valve.
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Evap issue will not cause misfire, you have a problem. There was no misfire before you tore into , correct? No code stored before?
Correct, running perfect before. also was running perfect just a few days ago. had not ran it in 4 days. started up perfect but then shot the code. what are your thoughts on the hose pressure? Interesting enough i don't loose collant.
As I said, I did mine to do a block test.
The theory being, a cracked block will only show it's symptoms when at operating temp. Thus, if you have misfires and overheating at temp, but run way below operating temp and don't get them, it's a good sign you have a crack.
Cylinder 2 misfire is typically a HG and not block.
TOP is stamped on the gasket. That's not Toward Oil Pan. Or maybe you didn't torque it right.
This job can go bad a million ways. I remember one time the parts manager came to me with a tech that was breaking head bolts on reassembly. I had never heard of that and asked him how far is 90 degrees. He got a stupid look on his face and scurried off.
Another common way this job goes bad is to get the end clamp for the intake gasket under the manifold. But that's not what you have going on here.
Another common way this job goes bad is to get the end clamp for the intake gasket under the manifold. But that's not what you have going on here.
Bad head job because? it gets hot? I am trying to understand and thank you for the feed back.. I am not loosing collant, and i am going to test for exhaust fumes in the collant this weekend, but I don't think thats what it is. can you elaborate?
Yes I understand what TOP stands for in this case. but can you elaborate on what aspect of a bad head job would give me this issue? again i don't lose collant and will test for exhaust fumes, but i don't think that is the issue. looking for feedback.. Thank you
Well if the head gasket was installed with the top on top it has to be a clamping failure. So you could have failed to blow the coolant out of the holes and really just clamped down on a pocket of coolant and not the top of the head. And then there is the whole torque thing itself. I've seen people torque the head to the first spec and not go around and do the 90 degrees twice. I've also seen people use the headbolts again and that causes this. Or you damaged the gasket when you put the head on it.
Before you rip it back apart you should try to figure out exactly whats going on. I personally would be doing a cylinder leakdown test on it. Then when you figure out exactly what cylinder or cylinders are having a problem you will be looking in one specific area and not the whole engine. Kind of do some investigation and then get it back apart.
From the sidelines: why is he a jackass? He's absolutely right. A stuck open thermostat will only affect how long it takes the engine to warm up. It has nothing to do with its final temp.
it has more to do with its final temp than you think. The Ecm will store a fault for unable to reach operating temp on most newer stuff. If the stat is stuck open then we are lucky that some engineer spent a bunch of time figuring out just how much coolant flow needs to be restricted to protect the engine.
My statement was that if you remove the stat on a D1 it would probably run too hot, and more than likely overheat if ambient temps got too high. That's because now nothing is restricting flow enough to keep coolant in the radiator long enough to cool.
Maybe I missed it, but did you install a Genuine thermostat yet or are you still running the aftermarket 180F thermostat?
Cracked block leads to blowing hoses, expansion tank, etc. the combustion chamber pressurized the cooling system.
listen to what Willy T said. The needle goes to 12 o’clock at approximately 130 degrees and doesn’t rise until 230 if I remember correctly.
I plumbed my coolant temp sender at the output before the thermostat, my gauges (oil temp, oil pressure, coolant temp, and coolant pressure) were marked numerically so I actually knew what the temps and pressure was. That’s when I noticed the the actual temperature relative to the factory gauge.
I clocked the gauges so the temp and coolant pressure needles were at 12 o’clock at proper temp and pressure.
Any time those needles were not at 12 o’clock I knew to shut down.
typically 240 degrees is getting into head gasket failure range.
You should start with a genuine thermostat like jimmy said.
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