Author Topic: 318IS M42 big air lock? (Read 4298 times)

finite · « **on:** February 07, 2009, 05:02:57 PM »

Hey all! Great forum.. I've just got my hands on a e30 318is, i was told it had had a M44 put in it with the M42 inlet and electronics... however I'm now convinced its an M42 engine out of an e36 with the old M42 inlet and electronics from the e30 M42.

Here's the problem (well one of many) - the temp guage doesn't rise (comes off rest with ignition but no further), and the heater doesn't blow hot air. I've replaced the thermostat and bled as per instructions on this forum but to no avail. The car is also extreemly hard to start when cold, after a few minutes it idles fine - been told that this could be the temp sensors?

So am I on the right lines when I think that it could be a big air lock in the coolant system which bleeding after the stat change hasn't cleared? This is causing the temp sensors not to pick up a reading and the heater not to get hot?

Or....?

tjts1 · « **Reply #1 on:** February 07, 2009, 10:55:35 PM »

You might be on to something. Once you have it filled up with coolant, the system needs to be bled of air bubbles. park the car with the front tires slightly higher than the rear and run the engine with the bleed screw on the left side of the radiator removed. This should help push any air bubbles trapped in the system to the top and out of the radiator.
I'm not sure about the cold start problem except to say that its a very common issue with these engine. Others know more about it. Its probably unrelated to the coolant issue.
good luck
Justin

Isamemon · « **Reply #2 on:** February 08, 2009, 01:01:16 AM »

I was told that you must use the thermostats that have the bleed hole in them and the bleed hole must be at the top

dont know if it is true,
my new one did not have the bleed hole, neither did the one that came out
havent been able to finish the head yet, so I dont know if it really makes a difference as I havent bled mine yet

papercutout · « **Reply #3 on:** February 08, 2009, 06:57:55 AM »

Thats not true about the thermostats, my thermostat (old and new) were official BMW ones, and they had no bleed hole.

But do what tjts1 said, run the engine with the bleed cap on the rad off, wait till bubbles have stopped appearing, then screw it back on and check the heating is working.

I can't help with the original problemo though.

xwill112x · « **Reply #4 on:** February 08, 2009, 10:19:22 AM »

Quote from: Isamemon;66104

I was told that you must use the thermostats that have the bleed hole in them and the bleed hole must be at the top

dont know if it is true,
my new one did not have the bleed hole, neither did the one that came out
havent been able to finish the head yet, so I dont know if it really makes a difference as I havent bled mine yet

take a baseball bat, and beat who ever told you that in the face.

LOL

the bleeder valve/screw is on the left side of the radiatior.

Isamemon · « **Reply #5 on:** February 08, 2009, 12:28:27 PM »

the comment came about after looking in my repair manual and it mentions using thermostats with the bleed hole and that they must orient up. which my new and old ones did not have, so I was bs'ing with a friend of mine who is a diesel mechanic and he was the one that said they will not bleed correct if they dont have the hole.

xwill112x · « **Reply #6 on:** February 08, 2009, 12:29:31 PM »

Quote from: Isamemon;66128

the comment came about after looking in my repair manual and it mentions using thermostats with the bleed hole and that they must orient up. which my new and old ones did not have, so I was bs'ing with a friend of mine who is a diesel mechanic and he was the one that said they will not bleed correct if they dont have the hole.

whatever he's smoking...please get me some.

bc its obviously some GOOD SHIT

tjts1 · « **Reply #7 on:** February 08, 2009, 01:04:29 PM »

It will bleed just fine once the engine is warmed up, thermostat opens and upper radiator hose gets hot. Just make sure to park the car with front tires facing up hill and engine running.

finite · « **Reply #8 on:** February 08, 2009, 02:45:26 PM »

Well here's the continuation of the saga!

My main thread about the car is here: http://www.m42club.com/forums/showthread.php?t=7825

I had a look at the situation today along with changing my lower sump gasket... well replacing with instant gasket anyway! Now the bottom hose on the rad is staying cold, the top hose gets hot, the radiator pretty much stays cold (a little warmth on the expansion tank side), the hoses to the bulkhead are hotter than they were but still not as hot as the top hose into the rad.

Temp sensor is still not working. Still no heat from heater.

I've finally managed to have a look at the head and it does have two sensors in it (blue (ecu) and brown (gauge)) so have ordred both. This week I will be doing the following:

1. Drain coolant again

2. Remove and refit thermostat again (how can I identify its the right one and working?)
3. Remove throttle body
4. Eliminate throttle body warming plate and simplify hoses under throttle body as per http://www.m42club.com/forums/showthread.php?t=2742
5. Rmove upper and lower inlet manifold, clean and powder coat
6. Replace brown and blue temp sensors and test (got code reader on the way)
7. Put it all back together and bleed. Couple of things on this - my bleed screw has been replaced by a normal bolt with o-ring and some washers, will this stop it from bleeding properly? Which way round should the heater hoses go?

I've also got to weld a patch over an inner wing hole, a hole in the bottom of both front wings and weld in the engine mounts (sheered bolts).

Should keep me busy!

I really appreciate all your help guys - please keep it coming, at the moment I've 8 weeks to go till we're off to the Nurburgring, unless I can get the coolant system working properly I'm not going