Temp Dillema

[ARTEMIS1759]

OK so I am back on leave from the military for 2 weeks and have 1994 GMC Yukon 4x4 2 door SLE with 5.7 and auto. Since I been gone in the last 6 months it won't heat up. It has a new radiator and a new thermostat was installed. I thought it could be the thermostat but not sure. I am just looking for ideas. There is no heat or luke warm heat and the temp guage reads right around 100. It runs fine but there is no heat. It seems to be loosing about 1 quart of coolant every 2 months. Anyone got ideas for me. I only got till the 17th. Thanks all.

[ford2custom]

First enjoy your time off; those two weeks go by pretty fast.

Usually it’s the other way around, too hot. You might try touching the heater hose going into the heater core at the fire wall, if it’s not hot then it could be the water pump leaking out coolant but it should get hot if that were the case. The thermostat could be bad even though you changed it.

I hope the coolant is not getting into the engine, check the dipstick just in case. I've had that happen before, Head gasket.

Richard

[ARTEMIS1759]

This one has me confused. First thing I checked was oil. Not milky. I am going to check to see if anything is heating up. Have not checked the core yet. I can't figure out why it is running so cold?

[1gary]

Under the last touched theory,it could have air trapped in the system.If it was a bad head gasket,you can take off the rad cap and wait for the thermostat to open.If there is a bad head gasket once the thermostat opened,you would see a stream of bubbles.Is there any white smoke coming out of the tail pipe??.That is after it warms up.

[ARTEMIS1759]

[QUOTE=1gary;379888]Under the last touched theory,it could have air trapped in the system.If it was a bad head gasket,you can take off the rad cap and wait for the thermostat to open.If there is a bad head gasket once the thermostat opened,you would see a stream of bubbles.Is there any white smoke coming out of the tail pipe??.That is after it warms up.

No smoke, milky oil, nothing??

[ford2custom]

Try blocking the radiator then watch the gauge. Put a piece of cardboard or some type of cover; just make sure you watch the gauge.

Richard

[jyardgirl]

are you sure that you thermostat is put in correctly.

[NTFDAY]

What is the anti-freeze ratio?

[1gary]

[QUOTE=ARTEMIS1759;379889]

Under the last touched theory,it could have air trapped in the system.If it was a bad head gasket,you can take off the rad cap and wait for the thermostat to open.If there is a bad head gasket once the thermostat opened,you would see a stream of bubbles.Is there any white smoke coming out of the tail pipe??.That is after it warms up.

No smoke, milky oil, nothing??

Suggest you don't over look the cap off/bubbles test.

[rspears]

Can you get your hands on an infrared heat gun to shoot engine/radiator/hoses and see what your temps really are? Like Barb said, are you sure the t-stat was put in the right direction with the element down into the manifold? Probably is, or you would be tending to run hot, then snap open once the whole housing got hot enough...(I think). Was the "new radiator" an OEM replacement, or did you put in something custom? Be sure the path from the filler neck to the coolant recovery tank is not blocked or you can get a vacuum lock on the system. New hoses with the new radiator? Bottom hose is not sucking closed is it? I lean towards air in the system - some Jeeps need to be parked on a steep uphill slant and vented (pressure off the system) to get the air out of the intake - never heard of it on a SBC though.
I've seen that there were lots of problems with deteriorating intake gaskets due to DexCool, which might explain your leak, but not your temperature issue.
http://www.consumeraffairs.com/autom...m_dexcool.html

[ARTEMIS1759]

ok ALL. gOT PART OF IT FIGURED OUT. fINALLY TOOK THE WATER NECK OFF THE INTAKE. WhILE I WAS GONE ONE OF MY SON'S SHADE TREE MECHANIC FRIENDS PUT TE t STAT IN. sO i PULL IT OFF. aFTER NOTICING IT WAS LEAKING IN TAT AREA. tHE oRING IS SITTING ON TOP OF THE T-STAT INSTEAD OF Wrapped around it. So now I got temp to 150 or 160 and a fair amount of heater. Sorry for the caps lock I don't feel like retyping all this lol. I think it may be the coolant mix now. The radiator was OE and the T stat came from my old parts store and I know those guys their shit. Maybe it is broke. Who knows I will check that too here.

[1gary]

ok ALL. gOT PART OF IT FIGURED OUT. fINALLY TOOK THE WATER NECK OFF THE INTAKE. WhILE I WAS GONE ONE OF MY SON'S SHADE TREE MECHANIC FRIENDS PUT TE t STAT IN. sO i PULL IT OFF. aFTER NOTICING IT WAS LEAKING IN TAT AREA. tHE oRING IS SITTING ON TOP OF THE T-STAT INSTEAD OF Wrapped around it. So now I got temp to 150 or 160 and a fair amount of heater. Sorry for the caps lock I don't feel like retyping all this lol. I think it may be the coolant mix now. The radiator was OE and the T stat came from my old parts store and I know those guys their shit. Maybe it is broke. Who knows I will check that too here.

Cool-thanks for the update.

[NTFDAY]

Your coolant mix should never exceed 50/50. A higher concentrate of anti freeze will cause it to run cooler.

[rspears]

Your coolant mix should never exceed 50/50. A higher concentrate of anti freeze will cause it to run cooler.

I did not know that more glycol would run cooler! Learned something today.

[kitz]

Your coolant mix should never exceed 50/50. A higher concentrate of anti freeze will cause it to run cooler.

I believe it would tend to run hotter. Pure water has the highest specific heat capacity. For a given flow rate when you add E-Glycol this drops and the fluid temps rise. In addition the mixture does not pump as efficiently as pure water so there's another penalty. These cause heat, not cold. In either case it is not going to result in more than a +/- 5 degree difference in an automotive application.

Looks like you have a 160 thermostat and you probably need a 185 IMO. This is especially true if the engine is fuel injected ..................

Kitz