M20 getting hot

[Dawskip]

Okay, when you squeeze the top hose, the very top hose from the thermostat housing, do you see coolant moving in the reservoir? or it nothing happening?

If nothing happens, it means there is a lot of air, if some coolant moves, you have some air, if you see the coolant level move decently, it is bled and the problem is somewhere else.

It flows into the tank — i know i have it bleeded lol everyone here is trying to tell me I don’t know how to bleed it



inwas at it again yesterday and noticed a few drips of coolant coming out of my exhaust, going to write it off as a cracked head probably and prep for a 20v or a turbo m20 swap

[S.J.1981]

I’d been doin this with no luck

Okay, when you squeeze the top hose, the very top hose from the thermostat housing, do you see coolant moving in the reservoir? or it nothing happening?

If nothing happens, it means there is a lot of air, if some coolant moves, you have some air, if you see the coolant level move decently, it is bled and the problem is somewhere else.

[Dawskip]

Is it possible it could be a dime/cluster issue?

I replaced my brown sensor on the thermostat and tightened the nut on the back of the cluster already.

[Dawskip]

Just to be sure, got to ask.

When you bled the system, was the heater set on max? (max heating)?

I just replaced the intake manifold gaskets a few days ago, it took me a while to bleed the system, it idled a bit hotter than it normally does, i actually overfilled the reservoir a bit to get bubbles coming out of the bleed screw. Then eventually pure coolant and no bubbles and now temp is spot on.

What i also like to do, is to bleed the system with the reservoir cap NOT tightened, then close the cap, wait a few minutes to build pressure, then open and close the screw a few times. If nothing comes out of the bleeder screw and the reservoir is full, close the cap. If the cap is closed, then make certain that the heater is on and let it idle, rev the engine a bit, basically let the system build pressure and it should help.

I’d been doin this with no luck

[Dawskip]

Update:

replaced the water pump belt as it was literally the last price I hadn’t fixed — no cigar.

One thing I did notice is that the left side of my radiator at the top is hot to the touch, however the right side is still cold, not sure if this is normal.

Starting to run out of hope here.

[S.J.1981]

Car is definitely bleed, and I’ve already replaced the fan clutch.

Just to be sure, got to ask.

When you bled the system, was the heater set on max? (max heating)?

I just replaced the intake manifold gaskets a few days ago, it took me a while to bleed the system, it idled a bit hotter than it normally does, i actually overfilled the reservoir a bit to get bubbles coming out of the bleed screw. Then eventually pure coolant and no bubbles and now temp is spot on.

What i also like to do, is to bleed the system with the reservoir cap NOT tightened, then close the cap, wait a few minutes to build pressure, then open and close the screw a few times. If nothing comes out of the bleeder screw and the reservoir is full, close the cap. If the cap is closed, then make certain that the heater is on and let it idle, rev the engine a bit, basically let the system build pressure and it should help.

[Dawskip]

Interesting, you should get coolant or air when you open the bleed screw as you are basically opening the system.

But let's back up the bus a minute as we are collectively missing something. How did the overheating start?

car ran great, jsut installed CAtuned silicone lines as a precaution. They don’t a provisional in the hoses for a secondary thermostat by the firewall, so I just removed it. That’s all I did, and now it won’t stay cool

[Dawskip]

Ran a compression test to be 10”% sure I didn’t have a blown head gasket, here’s what i got.

155

175

160

155

155



160

[tomstin]

I opened the bleed cap, some air bubbles came out then it stopped — no coolant or air.

Interesting, you should get coolant or air when you open the bleed screw as you are basically opening the system.

But let's back up the bus a minute as we are collectively missing something. How did the overheating start?

[Dawskip]

Update: opened the Coolant cap cold — was low on coolant even though I’m 100% positive it was topped off the last time I did it (which was yesterday), filled it up and continued to bleed it (jacked the front up, heat on high, etc). Keep getting air out which was good, got in the car and the heat was kicking as I revel it up to 1.5k, however when it dropped to idle there was a noticeable change in air temp, it got colder. I opened the bleed cap, some air bubbles came out then it stopped — no coolant or air. Closed it up, drove it around the block, got cold for a minute and went right back up to the middle mark.

im at a complete loss. Should i keep driving and trying to bleed? Could there jsut be a BIG air pocket?

[Vincenze]

I will give it a go -- however when I did take the last radiator off, coolant came out looking fine, but at this point anything is worth trying.

Well, if a kitchen kettle has scales in it, the water comes clean. You have to use chemicals to descale it.

[Dawskip]

I saw a lot of rust and scales inside of my M20 when I took off the head. The head was also covered in scales.

A lot of sand came out after using the flush and then pouring in water.

Try it and look if the water comes out clean.

Maybe, put the old radiator in order not to contaminate the new one.

I will give it a go -- however when I did take the last radiator off, coolant came out looking fine, but at this point anything is worth trying.

[Vincenze]

I have not tried doing that yet, but I did just put a brand new radiator in it.

I saw a lot of rust and scales inside of my M20 when I took off the head. The head was also covered in scales.

A lot of sand came out after using the flush and then pouring in water.

Try it and look if the water comes out clean.

Maybe, put the old radiator in order not to contaminate the new one.

[Dawskip]

Have you tried using a radiator flush a couple times?
Does the water come clean after using it?

The engine can be covered in scales inside. Leave the flush in the system for a day.

I have not tried doing that yet, but I did just put a brand new radiator in it.

[Vincenze]

Have you tried using a radiator flush a couple times?
Does the water come clean after using it?

The engine can be covered in scales inside. Leave the flush in the system for a day.