M20 getting hot

[Dawskip]

I’ve replaced every coolant related Item except the radiator, jsut put one on order and should be here soon.

Aside from this, I’ve also noticed that I don’t have an auxiliary fan, the previous owner must’ve removed it.

My question is, does anyone have a link or a picture to what the connector looks like/where it comes from? I want to remount one when I go to install the new radiator, but I’m not sure where it plugs in from/if the owner cut the existing wire.

[tomstin]

I don’t have a picture handy. Two things to check for the car running hot. First make sure you bled the air out. The easiest way is raise the nose of the car, run this enginee with the heat on and crack the bleeder screw. Second, if it runs fine on the highway and heats up in traffic the fan clutch (the one on the water pump) often is the problem.

[Dawskip]

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

[rlddlr53]

Do you have any cluster issues or jumping needles?

[Dawskip]

Installed a new thermostat and radiator today, means everything in the cooling system has been replaced.

it’s not as bad as it was before, but it’s still a tick or two above the middle, which I know it shouldn’t be.

Is there anything else that I can do to try and diagnose this?

[tomstin]

A few thoughts:

Is it better on the highway? Or hot all the time?

Is the heater blowing hot? (circulation issues)

Pictures of the fan and connections you may find here: https://www.r3vlimited.com/board/for...d-diy?t=246743

[Dawskip]

A few thoughts:

Is it better on the highway? Or hot all the time?

Is the heater blowing hot? (circulation issues)

Pictures of the fan and connections you may find here: https://www.r3vlimited.com/board/for...d-diy?t=246743

Blowing hot -- it seems to be running a tick or two over consistently, however every now and then, for almost no explainable reason it will dip back down to where it should be for a minute or two.

[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.

[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]

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]

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 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]

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?

[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]

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