Overheating issues 1600

[ct06033]

Okay, this is going to be along one. Last year, I refreshed my entire cooling system. New pump (supplied by PO), gaskets, radiator, hoses, thermostat, electric fan. Did a flush and thought I would be good. the temperature gauge would almost peg just starting the car. I decreased the ignition advance, got a 12lb pressure cap and the car seemed to run happier but still much hotter than before.

Fast forward to now, I am preparing for a long roadtrip and changed out the thermostat for a 160, burped everything, got a better electric fan. Now it runs in the top half/third of the temperature gauge.

I used a temp gun to measure temperatures and was reading 200F at the block/head and thermostat tower, but the upper hose and radiator read only about 150F. After doing a bit more research, I learned my head is from an early car, but the crank pully is from a late car. the water pump is for an early car but is mounted with a spacer.

My question is, aside from pulley/mounting differences, would using an early pump with the spacer cause flow issues? I am trying to decide if a new late model may solve my issues.

[spl310]

The water pump pulley from a late won't mount on an early pump unless holes are drilled or elongated. Has the pulley been modified? I would suspect that you have a late pump. It really shouldn't matter as that is the basic difference. There are some pumps with a stamped impeller which were intended for lower RPM applications iirc. That could be part of your issue.

[ct06033]

IIRC, the impeller looked like the blades were enclosed on both sides. I had no difficulty bolting it up but had to modify the pulley which i believe is for a late model to fit correctly. I assumed it was some minor issue as the rest looked identical between the old and new one. Thanks for confirming if the pump i have is working, I dont need to purchase a really pricey replacement.

Reading every past thread on the forum, it seems air bubbles in the block are a common cause of heating issues...

Would an air bubble in the block also cause flow issues? The radiator being 50F lower than the block seems like a large concern. I did burp the hoses and such but did not tilt the car when filling. I will try that tonight.

[Toptech360]

200 degrees at the head is ok, what is the temp at the bottom of the radiator vs the top?

[Gregs672000]

You want the bottom hose to be the coldest place as that means you rad has exchanged the heat. I'm not sure you're actually overheating. I would trust your temp gun over the gauge. Mine tended to show hotter than it was. I just replaced the sender but have not run the car since... rebuilding the engine. If you're still concerned, water wetter does work to reduce temps. Others may chime in on typical temps measured where you are measuring.

[ct06033]

When i go to burp tonight, Ill get things warmed up, take some more temperatures, and report back.

[mraitch]

FWIW, over the years, after changing coolant , and burping, I have run the car to hot with the overflow cap off, this allows all air to escape, And when I shut off it sucks coolant back into the engine.

NEVER had a problem with overheating as a consequence.

[Linda]

My experience is that you have to burp the heck out of it multiple times.
Also the amount of coolant that came out has to go back in. Easy to think you have filled it but it can take more.
Linda

[ct06033]

Hmmm I'll try the cap method... So tonight I went and jacked the front of the car up about 1.5ft then removed the rad cap and coolant was just below it. The thermostat housing spilled out fluid when I took that one off. Ran the car down the block to warm it up then started taking temps. Dash gauge read close to the overheat line but temps read as before. About 200 at the head, 160 just below the upper hose on the rad and 135 at the outlet.

I was letting it idle as I was taking temps and the radiator cap started leaking. Nothing came out of the overflow tank however which has a 16lb cap on it. I'm going to replace the radiator cap but not sure if there's anything else I can do. Ambient temps were in the 60s while all this was happening.

[spl310]

Your sending unit may be bad

[dads311]

I recently had almost the exact same readings on mine. Gauge was reading about 230, laser temp gun said 185 at thermostat tower, 185 at upper upper hose on radiator, 105 at lower hose, head temps read between 185 and 200, block was at about 100. I put in a new sending unit, burped it like crazy as I refilled and now my gauge reads about 185. Made me feel much better. I knew it was not overheating as there was never any boil over but it bites when the gauge says it is that hot.Oh and I have a 180 thermostat.
So +1 on a new sending unit if you have checked the gauge and the wiring to be sure there is no short to ground.

[ct06033]

I will replace the sending unit later on I think. I am more worried about actual engine health and a bit less about what the gauge reads since as long as I know how far off it is, I know that is "normal" temp. I just think it should read lower after replacing the radiator with an aluminum 3 row and a 160F thermostat. compared to other setups. Honestly, probably need to give the engine a nice refresh, I wouldnt be surprised if the head gasket was leaking.

[dads311]

I also have a 3 row aluminum radiator and when it is idling and warmed up the air coming through the radiator just below the inlet hose is warm. But the air at the lower hose it is ambient.
Take your temp gun along with you on your trip just for piece of mind. If the gauge stays about where it is now, your new "normal", during the trip you should be OK. Any change use your temp gun to verify what's going on.
Have a good trip

[ct06033]

I also have a 3 row aluminum radiator and when it is idling and warmed up the air coming through the radiator just below the inlet hose is warm. But the air at the lower hose it is ambient.
Take your temp gun along with you on your trip just for piece of mind. If the gauge stays about where it is now, your new "normal", during the trip you should be OK. Any change use your temp gun to verify what's going on.
Have a good trip

That is probably closer to what I was expecting. Is yours from champion? I found mine on ebay and I figured with a similar design and material, they cant really be that dissimilar from each other. I think im going to drain the radiator and fill with distilled as the fluid in it was looking really gross so i may have kicked up some rust or something during the refresh. Either way, pushing that muck through the system cant be helping things.

[Linda]

You might have a fair amount of muck in the block. It is not guaranteed to be flushed out with a regular coolant exchange.
Also not sure if your cap rating is correct, I thought it is supposed to be lower....like 7 lbs
Linda