m42 radiator + m50 = problem

[z3ds]

Hey guys

I think there is something wrong with radiator swap i did. I followed everything from the bimmerdiy on how to bleed an e36 m42.

When bleeding the cooling system, is it normal for the coolant to overflow from the radiator opening (rad cap off)when I rev the engine at 3k rpm while the bleeder valve is out? I was bleeding it for about 30min.

My temp guage was working before the swap and now it is not so I dont know if it is overheating or not.

6 months ago I replace my thermostat and my car just sat for all those months.

[golde30]

shouldnt take 30 min to bleed your system with the m42 radiator. i just bled my m42 in the parking lot of a mall b/c i blew a radiator hose, and it only took me about 15min. when i bled the system, i just filled the reservoir all the way to the top while engine was running, let it overflow a lil, then put the cap on, and opened the bleeder screw. air came out, coolant level went down, put more coolant in reservoir, capped it again, open bleeder, until nothing but coolant came out of bleeder. topped off the coolant, and went on my merry way.

[z3ds]

Thanks for the prompt reply , I'll go do that 1st thing tom. I'll post what happens.

[1990m3]

where in milwaukee are you?

[aeryk7]

Did you swap the the temp sender/ sensor onto the head that could be why you are not getting a temp reading.

[kylebes1]

You should back fill the engine from the driver's side hose... get it warm, let it cool back off and check it. It will "burp" as it cools.

[z3ds]

I wasn't able troubleshoot my car again , no progress yet too busy:(

where in milwaukee are you?

I live near UWM but my car is near 76th. Where you at in milwaukee?

Did you swap the the temp sender/ sensor onto the head that could be why you are not getting a temp reading.

Nope, I did not touch them. The temp gauge just stopped working.

You should back fill the engine from the driver's side hose... get it warm, let it cool back off and check it. It will "burp" as it cools.

that sounds like a good idea, I'll also do that.

[z3ds]

I was able to try to bleed the cooling system again today. I was gonna put some coolant on the radiator when i found out it was empty. I knew It had a good amount of coolant a week ago. Alas, it started leaking on the plastic to plastic joint on the reservior as i filled it up. %&*$#$!!!

Eventhough it was leaking (just drips every 2 seconds) i bled the system.
It was doing ok as the water came out on the bleeder hole for 10 -15 min while the engine run. I capped the hole and left the car to idle for another 10 min. BUt then, coolant started to seep out on the radiator cap. I made sure that the cap was tight but coolant still came out. The coolant was hot but not overheat hot as i was still able to touch the radiator and coolant with my bare hands.^*$*%&!!

I was using a radiator cap that is from the separated reservior style cooling system from an e30 325. Does any body know if they are interchangable with the m42 radiator cap?


Note to self: dont buy cheap radiator on ebay even if the seller has 100%.. http://cgi.ebay.com/ebaymotors/ws/eB...160979273&rd=1
(although i might be just lucky to have a bad one)

[z3ds]

Got a behr radiator, put it in, bled the system and now my car runs fine.
Also got my money back from the previous rad seller, nice

[AL GReeNeRy]

old topic but i need some help!

ive bled the system and its running fine, however my temp gauge is still inop. i have a 92 NV m50 in my 91 318is. which temp sensor do i need to use to get my gauge working right? all i can find is info on ob2 conversions.

[1990m3]

I've got the temp sensor from my 318is on the s50 motor. That way the temp sensor matches the gauge panel without issue. It has worked fine with a 318is radiator (currently installed) as well as a late model 325is radiator (e30/e36 style)

[FredK]

You need PN 12621710512. It is a brown, one pole temperature sender. If this doesn't work, make sure the coolant temperature sensor wire is hooked up at C101. If the wire is hooked up, and the temperature sensor still doesn't work, try tapping the cluster.

The nuts that secure the temperature gauge might be loose. This happened to me. The temperature gauge worked fine for a while, then after a few months, it magically stopped working.

[AL GReeNeRy]

yup realized i needed to swap sensors.. now my cars still overheating..

using an m42 radiator (brand new) and it feels like my thermostats not opening..

[FredK]

You said you bled the system--are you absolutely sure you worked out all the bubbles? I know I didn't at first, so when the needle started creeping up on my short test drive, I pulled over, opened the hood, then opened the expansion tank. Yes, this was definitely not a prudent idea.

Cold coolant shot straight into the air. I nearly crapped myself! Fortunately I was carrying some extra coolant, figuring I might run into an emergency on this shakedown test drive.

When I got back to my house, I used understeer.com's bleeding procedure. Turn the car on, hvac fan onto high, full heat, then crack open the bleeder screw with the radiator cap open, and rev the engine to 2500 rpm until the engine warms up a little bit and the bubbles stop coming out of the bleeder screw, then you rev a little bit more, kill the engine, allow the engine to cool, then top the expansion tank off.

Sometimes if you have a huge bubble in the system, the thermostat won't crack open because it's not touching coolant. Does you thermostat have a hole at the arrow that designates "up"? If it doesn't, bleeding can be a pain in the butt!

[AL GReeNeRy]

You said you bled the system--are you absolutely sure you worked out all the bubbles? I know I didn't at first, so when the needle started creeping up on my short test drive, I pulled over, opened the hood, then opened the expansion tank. Yes, this was definitely not a prudent idea.

Cold coolant shot straight into the air. I nearly crapped myself! Fortunately I was carrying some extra coolant, figuring I might run into an emergency on this shakedown test drive.

When I got back to my house, I used understeer.com's bleeding procedure. Turn the car on, hvac fan onto high, full heat, then crack open the bleeder screw with the radiator cap open, and rev the engine to 2500 rpm until the engine warms up a little bit and the bubbles stop coming out of the bleeder screw, then you rev a little bit more, kill the engine, allow the engine to cool, then top the expansion tank off.

Sometimes if you have a huge bubble in the system, the thermostat won't crack open because it's not touching coolant. Does you thermostat have a hole at the arrow that designates "up"? If it doesn't, bleeding can be a pain in the butt!

my tstat did have an arrow and i pointed it in the UP position. ive actually pulled it out and have been trying to drive the car without one, but it is STILL overheating. im almost positive i have a huge bubble somewhere, but i cant get it out. could my water pump cause an issue? also, i have the HVAC on full HOT and at high speed, but no hot air is coming out. could my heater core be clogged? i thought they either worked or leaked coolant...