Oh no! BMW's infamous cooling system strikes again it seems....

[Scania]

My e36 328i decided to overheat last night on the way home, well, I noticed it was 3/4 on the temp guage where normally, it would be bang in the middle.

I stopped and let it cool down and then rather stupidly removed the expansion tank cap!.

One shower of hot coolant later, I filled it back up and drove it gently back home the temperature stayed half way as per normal with no problem.

I've driven it again gently to my parents today (with the temp guage not moving beyond 1/2) where I've had it on flat ground and been bleeding the thing - I live on a hill - , lots of bubbles coming from the bleed screw when its removed and the car seems to have taken an awful lot of coolant.

I went out to get yet more coolant and the temp went back upto 3/4 yet almost immediately went straight back to 1/2 !

I'm wondering if either I have a water pump thats starting to fail, or possibly a dodgy thermostat?

It will be into the garage asap to get this sorted, theres definately something wrong, its had a habit for a while of losing nearly all of its coolant after a real hard hoon but the overheating is a new issue, bar giving it a bit of right foot to get it upto motorway speed on the sliproad last night, I was driving it gently following an HGV in the middle lane.....

The car has been pressure tested with no fault found.

Iirc, Invader had a similar problem which killed his M52 engined 328i, does any of this ring a bell mate?

Catch 22, need to get the car fixed asap but equally need the car......

Tempted to take it down a quiet lane & torch it ..... j/k

Any thoughts appreciated.

 

[Scania]

Hmm, fist thing I'd check is the coolant hoses, and maybe check the rad also to see if it has a leak?

The hoses are soft to the touch and the rad is less than 6 mths old (was replaced by the garage that supplied the car) theres a bit of what looks like limescale around the waterpump assembly (well, I think thats what it is!) I'll take a picture if it'll help? - I had said deposits investigated by a local garage that I trust (the same poeple who pressure tested it) and whilst they agreed that it had been leaking at some point, it seems that the coolant is not being lost from there any more.

Check the thermostat in a bucket of boiling water, and take your waterpump out to make sure it's a metal impellared one.

Bleeding these systems is almost impossible, my old 325i is still being refilled/rebled by its current owner a few times a month (proven HG not failed by garage), most of the issues are caused by air locks rather than HGF, although if you get an M52 too hot, you WILL warp the head.

Next time you bleed it, make sure that you have the front end jacked slightly (otherwise the heater matrix is actually the high-point in the system).

What is your bleed process anyway?

Cheers for the tips paradigm.

My bleed process involves removing the bleed screw, starting the engine & filling the rad with coolant until bubbles stop appearing from said bleed screw appeture, replace screw & cap, drive car & repeat.

Done this about 5 times this after.....

It behaved itself on the 12 mile or so trip back from my parents although the expansion tank level had gone down considerably (just above the sender) on my return home.

Topped it up again doing the same bleed procedure, again, lots of bubbles initially and then they stopped.

I was using hot water in my coolant mix btw, not chucking in cold....

 

[Scania]

Piccys...

^^ Bleed screw to the left of the rad cap (with a cross on it)
probably as much help as a chocolate fireguard, sorry.

 

[Scania]

Be very careful tightening that bleedscrew up. It only needs a quarter turn to seal it (especially with your heavy hands ).

I managed to snap mine off (it's a plastic screw) and get covered in hot coolant.

I tightened it up using a piece of brittle plastic which broke as soon as it was tighter than finger tight if you see what I mean. I managed to crack the expansion tank cap on my Scania by overtightening it a few days back....


InvaderGIR -Thanks for the info mate,very much appreciated.

No, it's a way that can sometimes temporally fix a leak that was used in like the 80s.

True enough, these days a few doses of radweld does a far better job, not to mention your coolant won't stink to high heaven after a few weeks....

 

[Scania]

First thing I would do is stop driving it until it is fixed properly as all you will be doing is causing more damage to the engine.

In an ideal world, obviously.

Alas, I don't have access to another car that'll get me to work ( which is a good half hour away) nor can I afford to take time off, public transport is not available either....

So, the cars getting limped along. I'm carrying lots of water and took over an hour to get to work today! - every time the temp guage started to climb above 1/2, I stopped, opened the bonnet & left the ignition on (fan) so she cooled down.... A bit of a pain in the rear, but thankfully the guage only moved twice and on both occasions went happily back to normal (with no coolant loss) after 15 minutes or so sitting at the side of the road - fingers crossed it'll be kind to me..... sods law however dictates this will end the way of Invader's 328i I fear and I freely conceed that I'm taking one hell of a risk albeit with a car thats worth in real terms,bugger all.

This tactic has stopped it blowing out water which its been doing over the weekend...

Its booked in for Thursday (the only day the garage had a loan car available), and its getting its "Inspection 2" plus a new water pump & thermostat.

Chuck an egg in it? What's the worst that can happen? ..

A Chickens life is wasted?

 

[Scania]

To be honest driving it and doing that isn't going to be good for the engine, but then as soon as the needle started moving on mine there was no stopping it from hitting red. I'd pull over as soon as I could (often in a space of a couple hundred yards from the needle moving a tiny bit) and it'd fly up to near the red before I'd even stopped.

Your's doesn't sound as bad as mine but I can't help but fear the worst with the fact it's being driven.

I hear what your saying mate, mine sits on 1/2 as normal and then very gradually starts to climb toward 3/4.

Never mind engine damage, I nearly went into the back of a Merc Sprinter yesterday, I was too busy watching the sodding temp guage and missed him slowing down infront of me....

 

[Scania]

Update.

New Thermostat,Water pump, Viscous Fan & assembly,something else for the cooling system but I forget what, cooling system flush & replacement coolant, gaskets for said pump etc and an "oil service"* but I got them to change the fuel & air filter whilst they were at it, finally, new rear brake pads and ABS sensor wires.

£40 short of £500 including VAT & labour,a lot to spend on a car thats probably worth a similar amount I suppose, on the other hand, this is the first time I've had to spend any money on it in nearly 7 months since I bought it so, I'm happy.

An added bonus, I'd always assumed the climate control was shafted in this car as I could barely get any heat from it regardless of what temperature I set it to, driving it back this morning, I found to my surprise that my heaters work after all! - gives an idea as to how little circulation was going through it I suppose....

I count myself lucky in the extreme given what happened to Invader's 328.


* Initially the plan was an Inspection II but we decided that thats due next time.