Cooling problems

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ramrod126

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I have a 2002 GMC Sonoma sls 2wd standard cab with the 2.2 4cyl.

The fan clutch was bad so instead of replacing that I bought a 16" electric fan. I just did the work this morning and everything seemed fine. The fan kicks on like it should but the temp never drops back down. I am thinking it may be the water pump but I want a second opinion.

Here are the symptoms. The truck heats up, the fan kicks on, it hits 190 degrees and I shut the truck off. The top radiator hose is quite hot but the bottom one is just warm. Against my better judgment I took the radiator cap off and the coolant in the opening was just luke warm. I started the truck with the cap off and saw no flow at all. Any ideas?


Edit, forgot to add. If I squeeze the bottom hose I can hear a gurgle from around the top hose.

Edit again: Forgot to mention that it is also a brand new radiator. The old one was leaking so I replaced it too.
 
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You going in the right direction, but to see flow in the top of the radiator the truck has to be up to full operating temperature, i.e. the thermostat has to be open.

So I would try your test again and make sure that you run the truck long enough to get the engine up to full temp.

If you have a IR temp gun you can use this to check the engine as it is warming up. (IR = Infrared).

Safety: make sure that you remove the rad cap before you start the truck, and that the truck is cold. That way you will not get burned.
 
When I had the cap off it was at 180+ degrees and no flow so I shut it off quick. I don't have IR but I do have a fluke with a temp probe add on.

Tomorrow I am going to pull the thermostat and run it to see what happens. If I still get no flow I will get a water pump. At 15 bucks from advance auto it is not a big deal I guess.
 
Plugged radiator??? Clogged with mixed coolants residue from dexcool and polyglycol.
 
Brand new radiator. Just put it in yesterday with the fan. I forgot to mention that in my original post. The old one had a leak.
 
180 degree F truck is just getting warmed up, normal operating temp is 195-220 degree F, remember the thermostat for your truck is 195F, and that is when the coolent will start to circulate to the rad.
 
Well, it got hot enough for the service engine light to come on.
 
You could have an air blockage at the thermostat.
I usually drill a 1/8 inch hole in the thermostat disc to allow air to pass.
Some thermostats I have seen already have a hole or a notch in the edge.

You did take the thermostat out of it's plastic, didn't you???:rolleyes:
 
Problem solved. Replaced the old thermostat with a 180 degree replacement. Everything works as it should now.
 
A 180 degree thermostat may cause 2002 4.3 to suck gas more than normal...
 
well lets wait and see how long it takes to put the check engine light on. It's going to set a code saying not reaching oprating temp (can't rember off hand exact code #) let us know if you get this code. Should only take a few days to get it.
 
The ecu will determine the engine is not up to temperature and will maintain the increased fuel delivery according to that temperature.
 
happy 2011 said:
well lets wait and see how long it takes to put the check engine light on. It's going to set a code saying not reaching oprating temp (can't rember off hand exact code #) let us know if you get this code. Should only take a few days to get it.
Click to expand...

I put almost 300 miles on it today with several stops and got nothing.
 
17 days later and still no light. I won't bother to update again.
 
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