2001 GMC Sierra 4.8

Chris Jones · Jan 1, 2009

I think my thermostat might be broke. Open broke. It takes a lot longer to warm up than I think it should. I don"t drive it much so I"m just not sure how long it should take but my Honda Civic takes right about 2 miles at 32F. The other day I drove the truck to work and it was over 5 miles before it reached normal operating temp. So today I looked to see where the thermostat is on it and I can"t see it anywhere. I see the water pump and the outlet with the hose going into the top of the radiator but it doesn"t have a thermostat housing like I expected. Can anyone give me any pointers? Would one of those scan tools Advance Auto or AutoZone has be able to tell me if it"s taking to long to warm up? Or is there any way to tell without just replacing the thermostat. It"s a 2001 with the 4.8 V8. It only has 18K miles on it. Nothing except oil changes and tire rotation has been done to it. Rather keep the mechanics away from it if I can.

Bob · Jan 1, 2009

The thermostat is in the lower water fitting at the front lower RH side of the engine.

The water fitting and thermostat are sold as a unit.

<img src = "http://www.byunspeed.com/images/SLP100223.jpg">

John B. · Jan 1, 2009

If your Sierra is a cast iron block and the car is an aluminum block there's the difference.

Anonymous-0 · Jan 1, 2009

I agree, I don't think it is broke either. We have 2 Honda Accords and a Trailblazer. The Chevy takes longer to warm up. It has a bigger engine (4.2 inline 6) that holds 7 quarts of oil and a bigger radiator. Just more to heat up - if it is up to temp in 5 miles at 32 degrees outside that seems normal to me.

Michael Soldan · Jan 1, 2009

I just had my 2001 Sierra in the shop for a new thermostat and I had to get the heater core flushed, now it warms up quiker and gives good heat, according to the mechanic, the heater core was the culprit. The thermostat is at the front of the block by the water pump, just follow the rad hose.

Chris Jones · Jan 1, 2009

Thanks, haven't seen one on the lower hose before but this truck has a strange radiator setup to me. I just don't quite get the surge tank with the radiator cap on it and no cap on the actual radiator. Guess now that I'm thinking of it I'll do a google for some info on how this setup works exactly. Why couldn't they have stuck with the old faithful design.

I guess this must be better in some way--maybe cost savings or parts revenue.

Chris Jones · Jan 1, 2009

Ok, I'll watch it awhile and see. I'm not sure if the blocks are aluminum or iron on either but there definitely is twice the oil in the Sierra and probably twice the coolant but then it's a bigger vehicle with over twice the displacement. But then again it doesn't turn as many rpms either so.... I wish I could remember how quick it was warming up when it was new.

Anonymous-0 · Jan 1, 2009

This car is now about 8 years old. Have you had the radiator flushed, and how many times? If you have not cahnaged the coolant on a regular schedule, then heater core is probably plugged up. When you un-plug it, may develope a leak, hope not. Tom

noncompos · Jan 1, 2009

That's probably a regular GM setup; my 2000 LW1 Saturn wagon has the same radiator setup: filler cap on the surge tank, none on the radiator.
This thing doesn't have a trans dipstick; you take a plug out of the trans to check the level!! Must've saved 'em a bundle for bonuses.

2001 GMC Sierra 4.8

Chris Jones

Member

Bob

Well-known Member

John B.

Well-known Member

Anonymous-0

Well-known Member

Michael Soldan

Well-known Member

Chris Jones

Member

Chris Jones

Member

Anonymous-0

Well-known Member

noncompos

Well-known Member

Similar threads