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Discussion Starter · #1 ·
I've got a 1996 e36 328i and have had some major engine work done as it had overheating probs.
The coolant system was pressurizing.

Traced to knackered threads in the block (common problem I hear) and a cracked head.
The block has now been helicoiled and a replacement head skimmed, rebuilt and fitted.

Now the car runs ok, its been checked and the HG is fine and good compression on all.
The problem is that the coolant is not circulating, even when bled up.
Its had a new thermostat, housing, water pump and a known good rad fitted.

Now, I'm not doing the work, its at a mechanic who's pretty good with BMWs and even he's having trouble tracing the problem.

His first suggestion was that the pump (pattern part) may have had the wrong wheel fitted and could be running in reverse, however I think its pretty unlikely.

I know theres a lot of people on here who know their stuff, so i'm just looking for suggestions as to what could be causing the problem.

I noticed, when I drove it that the heaters (if set to hot) would blow hot and cold randomly, but mostly cold.
As soon as it got past mid way on the gauge I switched it off, as I know the implications of the red light coming on!

Any help appreciated, but please only comment if you actually know what your on about, I dont need to check for small animals etc in my engine!

Thanks
 

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BFuk Legend
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Sounds like there is still an air lock in the system. I had the same problem with a 528 i put a head on. Had to bleed it 3 or four times over a couple of days. These can be a real pain to remove the air locks. :frown
 

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Discussion Starter · #3 ·
Thanks for the quick reply Steve, this car has been a royal PITA and i just want it sorted, I have heard about the bleeding probs, but I didnt have any problems bleeding it before the headwork.

What you are saying seems like the most likely problem though as all other components in the system are brand new
 

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Yeah. I had exactly the same problem. You just have too keep at it. Sometimes they give no probs and other times can be a right pain. Just keep trying mate and be patient. If this still causes problems i would pull the stat out and have that checked in case its not opening. Its not unheard of for some new parts to be u/s. Keep us posted how you get on. :thumbsup
 

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Its not unheard of for some new parts to be u/s. Keep us posted how you get on. :thumbsup
good advice there.does your spanner man still have the old thermostat?...he could even try running it with the stat disconnected.
if the old pump is still available,swap them out too.
 

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Discussion Starter · #6 ·
Old thermostat and pump have been binned, which is a bit of a shame. I'm tempted to just get the car back and persevere with bleeding it myself.

I'm wondering if the stat has got jammed from getting too hot, its not a genuine BMW one so might not be as robust
 

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It could do mate. As its quite easy to pull the stat out i would check it. When the stat is out put it in a clear jug or a saucepan and boil some water. The stat should open at about 90c. As it the easiest thing to check i would do that first if bleeding again does not cure it. Always start with the simple stuff first. 9 times out of ten its always a simple problem. :thumbsup
 

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Discussion Starter · #8 ·
Cheers for the input Steve, and Mark. I'm gonna have to be a bit more regular on here.
When I 1st signed up it was pretty quiet.

I get the guy who's got the car to check the stat, but TBH I would have thought he would check that first.
This is what I hate about getting other people to fix my car, I would have done it myself but just dont have the time at the mo!
 

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First question mate....has the car been left at all to overheat after all the work and head testing has been done??? Was the engine oil replaced for fresh oil after all the work was done?? Did the person doing all the work checked the bottom end for cracks signs of meltage etc??
 

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Also whils your bleeding the cooling system make sure you give it plenty of revs to get the air pushed out as it takes ages so if you give it a helping hand it takes a lot less time!
 

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1.Jack the front of the vehicle up onto stands as high as possible,
2.Turn the ignition on,engine off,heater on fan setting 1 and temperature fully hot,
3.Remove the rad cap/expansion cap,remove the bleed screw from the rad and IF you have them the bleed screw(s) from the thermostat housing/top hose, return pipe or EGR thermostat.
4.Fill the radiator up and keep pouring till there are no more air bubbles coming out from the bleeds, when good then install bleeds and tighten down(don't snap them),ensure the rubber O-rings/seals are still on the screws/on the bleed holes.
5.Suck some water out so it's not full to the brim, replace the cap and then start the car. Run her up and check for heat from the vents when warm and check if over heating still persists.
6.If good then check the water level again in the morning when cool.
 

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Discussion Starter · #13 ·
The guys doing the work is experienced, and I know he's a good mechanic.
He wouldnt have repaired the engine, had the block been damaged.

To be honest, when it overheated it was not driven for long as i'm aware of what can happen.
My only concern is that I took it to the mot station after the work was done, with the old oil in it.
I didnt drive it hard at all though and its only a short journey.

Its being bled out again tomorrow, so fingers crossed
 

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There is also the fact that alot of aftermarket water pumps these days especially for e36's have a plastic impeller which likes to fall off after a while but i've also heard of new ones doing it very soon after being fitted!
 

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Discussion Starter · #16 ·
Turned out to be a big airlock as expected, had to use a tool which practically sucks the hoses flat to withdraw the air.

Car is running good now, was misfiring but some fresh fuel cured that.

Fitted some eibach springs and its transformed the cars handling, managed to free up the seized front caliper.

Just need to fix the abs now!
 

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Turned out to be a big airlock as expected, had to use a tool which practically sucks the hoses flat to withdraw the air.

Car is running good now, was misfiring but some fresh fuel cured that.

Fitted some eibach springs and its transformed the cars handling, managed to free up the seized front caliper.

Just need to fix the abs now!
Or didn't get the front of the car up high enough, I have them doing a wheelie when I'm bleeding them, always works no problems :thumbsup

Had to do the same on a Rover 75 at work this week which the other mechanic couldn't bleed :cool, it's lucky I'm tall enough to reach still :rofl
 

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Discussion Starter · #19 ·
I forgot to mention on this, the water pump was replaced with one that has a cast impeller wheels.

The one I got from Euro car parts was next to useless, it has a tin plate wheel and should be avoided
 
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