2000 Tahoe 5.7 will not reach 195* please help

[andrewlolney]

It seems to me that the thermostat isn't working, new doesn't mean it is good.  Best bet is like stated above.  Either pull that one out, or get another one, put it in a pot of water and see at what temp it opens by the time the water boils.  Then you know for sure the T stat is good.

I did get another new one last night. Haven't had a chance to put it in yet. But yes I will put them both in water.

Thanks.

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[Doug_Scott]

If the coolant is going through the radiator and the temp in the ecu is 185, your 195 thermostat should be closed until the temp hits 195.,

Does your old Gmc have the same engine as your new truck?  Were it me, and 8f the thermostats were the same, I would swap them.  You know it does what you want it to do, be a quick way to show that. 

I have never seen an engine run too cool, seen hundreds if not thousands of engines running hot., 

 

I seriously doubt it is 183.3 with a properly working 195 thermostat. Hand held laser based temp meters can be had pretty cheaply, and are pretty accurate for reading temps of important things like the ass of a black squirrel walking away on a 90 degree F day. 

[Grumpy Bear]

This isn't as unusual as it seems during the winter months. Especially if the thermostat in question has a 'weep' hole (or jiggle pin) or an imperfect seal. I don't know that your application has one but....At freezing temperatures it takes little circulation to cool these more efficient motors. Even if it hasn't a leak, at colder temperatures and light loads (idle or slow speed work) the required rate of circulation is so low that even the slightest opening of the stat will hinder rated temperature levels from being reached. My 4.3 gas motor runs with the grill opening 80% closed (taped) when air temps are under 40F. All of my Honda's run a square of cardboard before the radiators. At idle they never come to heat no matter how long they run. 

[andrewlolney]

Alright so an update. Swapped thermostats. Almost no change. Also discovered whoever the dipsh#! Is working at the dealer that changed the coolant didn't cut it with water. I drained out about a gallon and a half and put back water. Tested the coolant and good to -20. Still didn't see a change after that. I'm going to leave it how it is for now. I have good heat. Well see how it does in the summer. This is a great group of folks. Thank you guys for all of the responses and help. I greatly appreciate it.

New problem. Came home for lunch and went to leave. Fired right up and died. Let it sit for 5 sec. Hit it again turned for a while. Ran for maybe 2 sec and died. Let it sit for about a 2-3 minutes. Tried it again. It ran and accelerated just fine. Later I left work with no problems and still hasn't done it again. About to meet my wife about 30 min away. Well see of it does it again. My gut says external fuel filter hoping it's not the pump. Which I can do...its just freaking cold out. So I'll start there. If you guys have any other suggestions please let me know.

Thanks,
Andrew

And it just rolled 100k today!

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[riverbanks]

100k,it's just a baby,and next time that starting issue happens, disconnect the electrical connection at MAF and try starting,they get weird,sorry about your low temp issue

[Jsdirt]

5 hours ago, andrewlolney said:

Alright so an update. Swapped thermostats. Almost no change. Also discovered whoever the dipsh#! Is working at the dealer that changed the coolant didn't cut it with water. I drained out about a gallon and a half and put back water. Tested the coolant and good to -20. Still didn't see a change after that. I'm going to leave it how it is for now. I have good heat. Well see how it does in the summer. This is a great group of folks. Thank you guys for all of the responses and help. I greatly appreciate it.

New problem. Came home for lunch and went to leave. Fired right up and died. Let it sit for 5 sec. Hit it again turned for a while. Ran for maybe 2 sec and died. Let it sit for about a 2-3 minutes. Tried it again. It ran and accelerated just fine. Later I left work with no problems and still hasn't done it again. About to meet my wife about 30 min away. Well see of it does it again. My gut says external fuel filter hoping it's not the pump. Which I can do...its just freaking cold out. So I'll start there. If you guys have any other suggestions please let me know.

Thanks,
Andrew

And it just rolled 100k today!

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Firing up and dying suggests there's either fuel pressure bleeding off where it shouldn't, or the in-tank regulator has failed. Fuel pressure check would confirm either one with similar readings. If it doesn't hold pressure for at least 10 minutes after shutting the engine off, there's a leak somewhere.