Weird cooling system troubles

So my new to me 79 Cressida seems to have cooling system issues that I can't seem to figure out. Sometimes when driving it the gauge reads right in the middle, but other times it runs almost to the H mark. There seems to be no rhyme or reason for it though. I have noticed the coolant has been low at times when it runs hot, but no white smoke at all.

I drove it last on Mothers Day and it was running really hot even though it was cool that day. I turned on the heat, and had nothing but cool air coming from the vents. Thought it was low on coolant again which it was. My thinking lead me to think that it was an air bubble in the system, and therefore no heat. Well I ran the car with the cap off the radiator in the garage for close to an hour this afternoon while revving the engine to warm it up more, and also letting it idle. The temp gauge ran up to around the half way point, but not quite. It seemed the radiator wasn't really flowing like I thought it should, but I am almost sure the thermostat opened, as the radiator did bubble at times.

I checked the radiator hoses with my infrared heat gun and got 115 on the lower hose, 150 on the upper,165 on one of the heater core hoses, and 145 on the other. The thermostat housing read 175* on the aluminum surface.

I still had no heat in the car. Also the oil looks fine, but the coolant looks like it has something in it that looks odd, but nothing like the iced coffee with cream concoction that I had in the cooling system of my Mitsubishi van last summer when I found the cracked head. Take a look at the picture I snapped, and tell me what you think.

I am afraid it is oil, and that means a bad head gasket even though it was just done.

Is it possible that the head gasket is bad, and it leaks worse when pressurized and hot? I ask that because I have pressure tested the cooling system, and found no leaks at all. Maybe when it is hot it makes it leak?

I know the seller put a new gasket on the engine when he replaced it, but that doesn't mean the head isn't warped, or cracked I suppose.

Any help would be greatly appreciated.

Chris

If the PO didn't clean it correctly(flush with a detergent), it will still have crap in the coolant. You would have milkshake in the oil if the HG blew again. Are you sure the thermostat is any good and the right one? Radiator cap? Check the hose routing too.

I bought a new thermostat, but I have not had time to install it yet. The PO replaced the engine due to the old one melting down before he even got the car. He told me he put a new head gasket on it while the engine was out. The coolant doesn't look like the milk shake, but it also doesn't look perfect either. Not sure if it is the start of the milk shake process though.

I am burned out on cars right now, and am frustrated with this car. I love it, but can't stand having to repair it right now with all the other stuff I have going on.

start with a good flush, maybe have the radiator boiled, and a new Tstat. How old are the hoses? They can collapse internally

That looks less like milkshake and more like leftover stop leak in the system. I'd bet they didn't disconnect the heater core like you are supposed to when you use that garbage and plugged it while the actual leak was never fixed...

i believe Slick is onto something there. +1 to leftover Bars Leak.

You know, come to think of it, do you have tangible proof that he actually did the head gasket? Or are you just going on his word?

I suppose it's plausible that the original overheated engine went through a can of Bar's in an attempt to save it, and this is just residual crap left in the cooling system...but the "half empty" part of me thinks the guy may have just "fixed" it with a can of Bar's.

Could go either way, I guess.

Also check to make sure that head gasket is oriented properly although the port blocked is oil galley, it could still affect temps.

Temp Gage fluctuation and no heat tells me there's air in the system. When you do all this, is the heat turned on?

Second: Whenever you add radiator stop leak it heads right for the heater core first.

Disconnect the heater core lines and give it a good douching by itself to ensure it's clear and flowing well.

x2

I'm betting heater core is obstructed, making it impossible to burp.

back flush, separately.

No heat in the core, or no heat blowing?....is it a blend type of setup?

No heat blowing. I believe it is a blend sort of setup with the auto-climate control. It has a valve on the heater hose entering the heater core in the engine bay that seems to vary the amount of hot water enters the core. Just a guess at that though. It does have an electrical connection, and a vacuum diaphragm.

The engine was replaced by the guy I bought it from, and he told me he took the old head off the engine to find nasty things going on which he had pics of. He also told me he did the head gasket on the new engine before putting it on the car.

Chris

So I pulled the hoses off of the heater core at the firewall, and ran compressed air through each fitting. The air flowed just fine. I by passed the electrical/vacuum actuator that controls the flow of coolant for what seems to be controlled by the auto climate control. Still no heat. I changed the thermostat, and it seems to be temperature wise just fine in the garage. Why no heat? Could the HVAC system be vacuum actuated, and I have a leak somewhere? Could there be a valve like on my REPU that allows the heat to flow into the heater core that is controlled by a cable, or is the apparatus on the firewall controlling this? Broken, or misaligned cable? Any help would be greatly appreciated.

Anyone?

Stuff in the coolant looks like K-Seal, a magic elixir that sometimes fixes combustion leaks without having to remove the antifreeze like most block-weld products require.

I used it once on a 13B with a weepy coolant seal and it held for a couple months until I overheated the snot out of it which killed the repair. I have also used it in a customer's car with success... and a couple times with no success.

And it makes your coolant look like Goldschlager.

What engine?

Start eliminating things. Slam the temp control back and forth, can you hear the blend door banging on its seats like it should? Replace the coolant flow controller with a ball valve.

I would put in a cheap aftermarket mech gauge rather than trust the factory one. Like the set of three for $15 at autozone or where ever.

Next I would add in a higher bleed point if you don't have one. You can get plastic T's with a screw on cap for a couple of bucks at your local car parts store too. Top off the whole cooling system at the highest point. Heat the car up to 170*F+ and then cool down and check the level of coolant.

Some cooling systems trap air around the sensor locations and other annoying places.

For the stuff in the coolant I would just watch your coolant temps closely and see if any more of that stuff comes up. Could be someone used the same pan to catch coolant as they did oil (or some other fluid) but didn't clean the pan out

I had the impeller come off a water pump and it acted similar to what you describe. When you run it with the radiator cap off can you see signs of coolant flow?

Don49 wrote: I had the impeller come off a water pump and it acted similar to what you describe. When you run it with the radiator cap off can you see signs of coolant flow?

Good thought, a car that old might actually run thermosiphon OK.

I don't see signs of coolant flow in the radiator with the radiator cap off. I drove the car this afternoon for about a mile after it idled in my driveway for about 3-4 minutes, and the temp got so hot in that mile that it boiled over. I shut it down, and let it cool for a 10 minutes or so, and drove back home with the temp not going much higher than the middle point.

I found a vacuum controlled unit under the dash that when moved by hand actually made heat come from the vents. Now I know there is a vacuum leak or hose that isn't attached at all or improperly.

The bigger issue is the hot running/boiling over. The water pump looks brand new, but that doesn't mean it hasn't failed.

At this point I just want to sell this thing. Anyone interested? I am so frustrated I would probably take a major lose on this thing.

Chris

Thought, craptastic Chinese water pump has a a loose impeller that likes to spin on its shaft, till things heat up and it locks back on.

I tend to agree. I think you need a water pump. You should see the coolant flowing through the rad once it is up to temp and or as it comes up to temp you should see extreme movement of the coolant when the thermostat opens. If you are not seeing this replace the water pump.

I would also do a leak down test of the cooling system just to once and for all determine if there is a leak issue.

Yeah by the way things are sounding, the water pump could be junk. Who knows how long ago the PO put it on except the PO. I had a Durajunk water pump only last a year on my Durango.

Could also be the reason why there is no heat.

I did a leak down test on the cooling system, and found no leaks a few weeks ago. I figured out the no heat problem with the discovery of the vacuum actuated unit under the dash that blends hot and cold air for the automatic climate control. Just need to get it a vacuum signal.

Chris

Took the car for a 1 mile trip to the local convenience store, shut it off, went inside, and drove 1 mile home, and by the time I was in the driveway it was boiling over. Anymore ideas? Could it be blocked up somehow? I don't seem to be able to find a new radiator listed on the popular parts site, so I may have to get this one repaired if it is the trouble. Ay help would be greatly appreciated.