Running a little warm

My temp gauge liked to peg itself out beyond H and did so fast... so I figured it was time to replace coolant, temp sender, and 192* thermostat. So, I did that this afternoon. All the aforementioned pieces are now new. Did it while I was installing a block heater on my lower radiator hose.

However, the temp gauge still creeps up almost all the way to H... just a bit off. It took its time doing it, so I know some of the replacements worked. What else do I need to look at? I've heard of "burping" the coolant system after draining and refilling it. Do I need to do that? Would that affect the temp?

Thanks!

 

Plugged radiator? Leaking water pump? air trapped in the block?

The t-stat should have had a small hole in the metal. That hole should have been installed so that it was toward the top of the housing. This allows air to escape the block. That's what they mean by burping. Getting all the air out of the block.

Does th radiator look rusty or a lot of gunk in it? Was the old coolant brown when you drained it?

 

Can you confirm it's really running hot and not an issue with the temp gauge/sender? If you have a non contact temp gauge (harbor freight), you can confirm if it's really a temperature issue and not a gauge issue.

 

Old coolant was thick, but a good green. The radiator isn't pretty on the exterior, but looks pretty clean on the inside.

I don't have any leaks off the block, coolant or otherwise. So, I'm fairly certain that the water pump is in good shape.

My best guess is the air. Don't know where I put that hole, but I saw it when I was putting it in... will have to pull and double-check. Any other way to burp it?

Thanks!

 

Would have to find a non-contact thermometer. I'll ask around.

 

Had a pickup truck radiator scale up on me. It had boiled over and I refilled with well water. Boiled over again and I refilled. Eventually I could not climb a hill without the temp gage pegging. Had to run with heater on full blast in August to get home (a LONG trip).

When it boils over it leaves hard scale in the inside surfaces if you are using water with a lot of minerals. Good reason to use distilled water and maintain coolant system.

 

If it's scaled/plugged on the inside a good radiator shop should be able to revive it for around $100 or less.

 

One thing I just thought about. What condition is the radiator cap in? Is the rubber cracked or deformed. May need to replace it.

 

Good thought... I'll check that this weekend. If I recall, the rubber was pretty done on the seal.

 

If it overheats quickly, run it with the radiator cap removed and watch for bubbles, if it bubbles you probably have a blown/leaking head gasket on one cylinder. Some white smoke from exhaust on start up would be an indication of this condition. Hope this help in diagnosing the problem.

 

Remember, temperature sensors only read WATER temperature, not air temperature. If you have an air bubble, your temp gauge would not go up. (I learned this the hard way. I popped a radiator hose in hs, had a "hot" reading for a few miles, then it went away. I cooked the head gasket right out of my poor truck!)

If you have a non-moving air bubble, your water pump is not moving the coolant.