What am I missing!!! (over heating...

[HeathMO]

Ok so I have my m20 swap up and going but I can not keep it cool to save my life!!! Started with a crappy perm cool fan and I had temp creep. I got a bigger maradyne fan and this thing won't keep it cool either!

I am running a m3 dual core aluminum radiator and I believe a 185f thermostat and a brand new water pump and I have burped the system. both fans are rated for over 2000cfm btw

[tlapham]

185 thermostat is too high.... try 180.

[DougIng]

The stock E30 325i thermostat is 80C/176F. I have that in my car with the original 323i fan and it runs very cool - 1/4 on the gauge.

My fan runs all the time. Does yours? I tried running without it and got the same behavior you did. It sat at halfway but would creep very quickly until I got moving again.

[HeathMO]

The stock E30 325i thermostat is 80C/176F. I have that in my car with the original 323i fan and it runs very cool - 1/4 on the gauge.

My fan runs all the time. Does yours? I tried running without it and got the same behavior you did. It sat at halfway but would creep very quickly until I got moving again.

Im using an adjustable fan switch so I can set the electric fan to start up pretty early I'm betting you think that would help cuz even with the fan on the temp creeps up

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Sorry just checked it is a 176 thermostat and I just checked it it is opening

[luis320i]

I had the following experience , hot cooling temp. , so I remove the thermostat , which is inside a metal/aluminum sleeve and it was very clogged and dirty , so I cleaned and make sure it was in the correct position , checked that was opening with hot water in a bucket and later closing when cool , and problem solved . Hope it helps .

[epmedia]

You also have to set the heater valve on full hot when bleeding the coolant system.

[bassboy3313]

I assume you are still running an expansion tank as well, right?

[dreiermann]

If you are running lean, that could cause it to be hot.

[HeathMO]

I assume you are still running an expansion tank as well, right?

Yes I am

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If you are running lean, that could cause it to be hot.

I don't think that's it if anything it smells really rich

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I'm gunna try bleeding again today when I get off work. I'll report back. Also my fan is mounted about 1/2 an inch off the core is that to much??

[HeathMO]

Ok update time! bled the system like crazy!!!! I got a ton of air out. its not toping out the temp gauge any more but it does hang out between the half way and 3/4 mark mostly on the high end is this ok/normal for an m20 swap?

Im going to use a thermometer tomorrow and check the radiator temps see if I can get a clue as to if its holding at operating temps or higher.

My m10 would sit at the half way and go slightly over when driving hard in hot weather.

[tlapham]

You should idle it with the radiator cap off, fan on, constantly topping off, until no more bubbles come up and it's warmed up. Rev the engine occasionally, too.

[HeathMO]

Yup exactly what I did but it still sits between the middle and 3/4 mark

[cgifool]

That seems too high. My 323 (m20) needle stays right dead center (or less).

Perhaps there is corrosion in the temp sensor wires? Or maybe a different spec for 4-cyl temp gauge vs 6-cyl? (doubtful).

If there's extra resistance in the temp sensor wires, would that make it read higher, or lower?

[Starmountainkid]

I had either a slightly warped head or leaky head gasket that made my e21 run hot. If all else fails, might think about that.

[HeathMO]

If there was resistance in the wire it would make it read higher. Im gunna try moving my fan a little closer to the radiator see if driving it and having more air flow makes a difference also going to try a little more bleeding and I know Ive got the twitchy gauge symptom so if it comes to it I might try and pull the cluster and fix that

[tlapham]

Rent a coolant system pressure tester. That will tell you if you have any cracks or head gasket issues. Also, how is your oil pressure?

[epmedia]

If there's extra resistance in the temp sensor wires, would that make it read higher, or lower?

lower

[HeathMO]

well I guess it would depend on the gauge and sensors. there are 2 types of thermistors

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OK update so I had a hose crack so I had to rebelled and all that good stuff but I drove it around and it is staying pretty much right at the middle mark just creeps over it every once in a while but even driving hard it stayed cool so I'll see how it goes maybe I'll add a small aux fan to the system but for now at least I can drive it to work again!

[DougIng]

Awesome! Good for you.