S52 w/ AC cooling problems

[Strelok]

So I just bought a really nice OBD2 S52 swapped E30. It's a really well put together car but it's my first swapped vehicle so I'm still learning a bit.

It's been having overheating issues since I bought it. Highway driving is mostly fine with some occasional jaunts past 1/2, but city/traffic driving is very problematic. In stop and go the gauge will creep past 1/2, past 3/4 and nearly to the red until I'm forced to turn the heat on to cool it down. This is obviously exacerbated by running the AC, but even turning it off doesn't seem to cool the car down much once it starts climbing.

This was today after a quick run down the interstate and then some stop and go in stoplights:


The entire cooling system is less than 2 years old with less than 10k miles on it. Radiator, t-stat, pump, and hoses were all replaced with high quality OEM parts including a BEHR E36 rad. I just replaced the stock pusher fan with a 1600 CFM SPAL unit and have confirmed both high and low speed modes work. Kicks on low when AC is on and kicks into high once the gauge passes a certain point. There is no puller fan due to clearance issues. I can't 100% guarantee the system is bled but the PO drove it around for 2 years since the cooling system overhaul, and I did park it on an incline today and rev it a bit with the heat on in hopes of getting any remaining bubbles out. Coolant level is fine, and I am running blue BMW coolant. Ambient temps in my area are around 85-90F currently.

I took some readings with an IR thermometer while the gauge was sitting a hair above 3/4 and got the following:

Upper hose: 195F
T-stat hosing: 172F
Lower hose: 180F

I can't really imagine what the problem is aside from a faulty gauge/sender or a bad HG, but I have no HG symptoms. Help is appreciated before I give up and take it to my local swap guru later this week.

Thanks!

[ForcedFirebird]

You really need 2 fans when the condenser is hot (ie A/C on), but based on your IR readings, you are fine. The stock e30 electric fan comes on at 205°f. 205° is not even "overheating".

It seems to me that your gauge is faulty. The 3/4 mark should be around 215°f, 220+ is red.

[Strelok]

Thanks. The gauge does occasionally jump around just a little bit, and I have to tap it every time I start the car to get it reading. So I guess the ground may be suspect.

[Codym42]

Generally, if you're running an A/C condenser, you'll want a puller fan as well. I had to shave the water pump shaft to fit my slim Spal (m42 radiator w/m52). With that said, your temps look good. I'd suspect a faulty gauge cluster. I had a similar issue with my m42 a few years ago. The gauge would always read at the 3/4 mark but the engine was running at normal temps. It turned out to be an issue with the SI board in the cluster.

[m3boost]

I have a mechanical fan and fan clutch on mine including the stock electric fan.. You definitely need another fan..

[Strelok]

Thanks everyone. I threw a new gauge in and the temps were mostly the same. I'm currently looking into adding a clutch fan and hoping there's enough clearance. Someone on my local facebook group told me I need to run an M20 fan mounted on the back of an E36 clutch. Does this sound right for fitment with an E36 BEHR rad?

[E30335i]

I think you need to swap your electric fan switch, have it come on a lot earlier like 80/88C.
The switch from a e36 ti should do it


Sent from my iPhone using Tapatalk

[ForcedFirebird]

Thanks everyone. I threw a new gauge in and the temps were mostly the same. I'm currently looking into adding a clutch fan and hoping there's enough clearance. Someone on my local facebook group told me I need to run an M20 fan mounted on the back of an E36 clutch. Does this sound right for fitment with an E36 BEHR rad?

I don't think you will have much (enough) room. A clutch fan puts the fan right up against the radiator, which solid mounts will allow it, but if you have poly/rubber engine mounts, you will be shredding your radiator.

Again, your car isn't overheating! 190-205 is completely normal. I am always using the IR thermometer on cars (work on e30/36's daily), and you are well within range.


BUT, your A/C will blow colder if you can get the temp of the condenser down.



The stock thermostat opens at 197-198f (92c). If you have a dual pole switch, the high speed won't even come on until over 100c (past boiling, or 217f). This is 1998 stock e36 vehicle specifications...

[m3boost]

Use this fan blade with a Meyle e36 fan clutch..
https://www.ecstuning.com/b-genuine-...522243303~geb/

[ForcedFirebird]

Use this fan blade with a Meyle e36 fan clutch..
https://www.ecstuning.com/b-genuine-...522243303~geb/

Nice find! Members here years ago would use the Audi diesel fan, but it was made for counter clockwise rotation (blew towards the radiator). I bought one years ago, and actually just threw it in the garbage last week.

[Strelok]

Use this fan blade with a Meyle e36 fan clutch..
https://www.ecstuning.com/b-genuine-...522243303~geb/

Thanks, I actually ordered this fan last night! I got the kit though that has a Vemo clutch, hopefully it works OK. While my temps aren't terrible, my AC really doesn't work well and I like my cars to run cool so I think having this plus the big electric fan on the condenser will get it running where I want it.

[ForcedFirebird]

I like my cars to run cool

It's actually not good for an engine to run too cool. Keep it in the 170's at minimum. I have found that they actually make the most power at 195....


also, I hope you didn't order from ECS. Not sure if you heard what's going on with the company, but they just did a hostile takeover at Turner Motorsports parts division. That listing says it will ship Sept 10th, expect at least 60-90 after that...

[ZekeTheSneak]

Stupid question but you are using the e30 brown coolant temp sensor? Obd1 or 2? Obd2 you still need to use the brown coolant temp sensor and cut two of the wires going to the stock ond2 sensor

[ForcedFirebird]

Stupid question but you are using the e30 brown coolant temp sensor? Obd1 or 2? Obd2 you still need to use the brown coolant temp sensor and cut two of the wires going to the stock ond2 sensor

Brown is for the gauge. The resistance on the e36 sender does not match the e30 resistance and the gauge will read wrong.

[m3boost]

Thanks, I actually ordered this fan last night! I got the kit though that has a Vemo clutch, hopefully it works OK. While my temps aren't terrible, my AC really doesn't work well and I like my cars to run cool so I think having this plus the big electric fan on the condenser will get it running where I want it.

I personally like the meyle clutch.. Its a little tighter and pulls more air at idle than most other clutches