BMW radiator leak free at last but not sure about the bottom hose.

[Vince70]

After getting rid of the totally reliable rover I’ve now gone back my old BMWs and all of them have had coolant issues and just wondering if I’m unlucky.

First off my Z3 (M44) yesterday deciding to leak coolant from the radiator in a spectacular fashion and last year it needed a new thermostat and expansion bottle so a new radiator will be fitted this weekend.

 

So not to worry I have two more sitting about and one of those needed a new thermostat (m44 again) last weekend but I’m too tight to pay a months tax on that one so I thought I would just use number 3

 

So this one I’ve just found out is also losing a little coolant so I changed the expansion tank and cap also on that one and it’s still doing it so it looks like I’ve a couple of radiators to fit sooner rather than later and was just wondering if I’m unlucky or are BMW crap at making rads and thermostats.

[Schaefft]

I've never had a problem with my E39 apart from a leaky thermostat housing gasket and pin sized hole in one of the hoses due to age. All cooling system components on the inline6s are a piece of piss to replace since accessibility is pretty good. I'd make sure you find the leak first before throwing parts at it.

[Lord Sterling]

Rover then BMW with coolant leakages. Yep, that is exactly what is happening to me right now. Every Rover (apart from the '95 827 Sterling) has had some sort of cooling related issue and now my e46 is taking the rains. The leaking in the BMW is getting worse and I have to wait until the end of the month when I get paid to put the car in for repairs, and maybe then maybe for once in my life I can have a car of my own that doesn't constantly find ways of letting coolant escape.

[MikeR]

I find the worst aspect of modern leccy fan cooling systems is that the engine temp is cycled from  stinkin hot to cool when the fan cuts in , I am sure this is not good for the engine and its other bits ,

 

my Volvo had a viscus fan system , that had a needle that stayed put whatever the weather or engine speed , and with its ducted fan system around the rad , it could clear the drive of leaves

 

some cars I wondered if the needle was going to pop out of the top of the temp gauge before the fan cut in !!!

 

must admit the Focus is good at keeping the temp steady with its twin fan system ..

[lisbon_road]

I'd bear in mind MikeR that the ECU on a lot of cars processes the data from the temperature sender and if it is within a reasonable range, puts the needle bang in the middle.  This gives the impression of maintaining a steady temperature when in reality, the temperature may be fluctuating quite a lot.  Whether that was the case with your Volvo or not, I don't know of course and there is something in what you are saying.

 

Also I've seen a car where (as you describe it) the needle was bending around the red area.  By fitting a different sender, it appeared to switch the fan on at a more sensible temperature - in reality the same of course.

[sutty2006]

Electric water pumps....... pffffft.

[MikeR]

Electric water pumps....... pffffft.

electric and water .......and built as cheaply as poss !

[HMC]

BMW cooling systems of the period do seem to need an eye kept on them as age and miles rack up that's for sure, I tend to think of the cooling system being largely made of service items on these....

 

E39 528i - expansiontank, thermostat, hoses

 

E46 318i - dead rad fan and or electrical circuit that operated it (VERY common apparently) thermostat, hoses.

 

E46 330d- v slight coolant leak, viscous fan which sounded like a helicopter on take off trickling through London traffic the other day so it's deffo working when things hot up at least.

[castros_bro]

My BMW R60/5's cooling is fine.

[sierraman]

They are a load of cack these days, years ago a BMW was a quality car, the build was a cut above. If anything now they are probably no better than a Renault.

[spike60]

Sorry to go against the grain but I've had few problems, a heater matrix in a e34 540i I owned for 11 years and 125k miles.. I also had a e34 525 Tds for umpteen years taken to 254k miles which had a thermostat due to being a cold arse. Current Bmw fleet are e39 530d touring owned 3.5 years currently on 264k and a 2.8 Z3 owned 6 years currently on 104k, neither with any cooling problems while here.

Surely Bmw will only buy radiators in from Valeo or whoever, same as other makers?

[warninglight]

Aye BMW don't make radiators, they just fit them!

 

It sounds like it may be worth your while getting one of those Chinese coolant pressure test kits. I bought one when my (BMW based) Range rover was losing coolant only under high load. A few drops of UV dye, a blacklight and the ability to pump the whole system to 13psi or so is ace. In the year or so I've had it, I've used it loads. Think they're £40 or so on ebay/Amazon.

[Crispian_J_Hotson]

My touring cooling system is fine. I reckon the brakes on it are shocking though, needing some caliper work every-single-time I change the pads. The 635's brakes are shite too... and dead. Why, even the discovery that passed through BMW's care back in 2001 also has shite brakes.

[Vince70]

So today my new radiator arrived and as would be expected the wrong radiator was sent out but I decided to crack on and remove the old one anyway.

 

Once the old one was removed I thought it would be a good idea to have a look of the belt and it didn’t look good but it’s lasted 22 years so it hasn’t done bad.

 

So while at it I thought it would be wise to change the pump as I had the thing apart but couldn’t get the thing off and now have bent big spanner’s and I also tried the 10mm M6 trick to push it off but nothing seems to budge the thing so it’s now soaking in plus gas and I’ve got the hump lol.

[Vince70]

I’ve now got the pump off with a lot of persuasion from a crowbar and lucky no damage was done to the car but I managed to pick up a few scuffs on the way.

 

The pump that came off was the original 1996 plastic blade job so it didn’t do bad and to be honest the only play in it I think is what I did from twating it with hammers so I better take it back about shite cooling systems on BMWs

 

I wouldn’t mind but I bought the most expensive pump that GSF had only to find that’s also got a plastic impeller blade lol

Here’s the original in all it’s glory I used washing up liquid around the rubber seal on the new pump to help it on so I hope it doesn’t leak.

[Tamworthbay]

It’s the only issue on my E46, it uses a tiny amount of coolant (about a litre every three- six months). No idea where it goes and it doesn’t seem to be distance related. When we went to Scotland last year I did 1800miles in 9 day’s and it was full when I got back. Sometimes I only do 2000 miles in three months and it will need a

half a litre..

[Vince70]

Oh I forgot about the good advice the Rev gave me about smearing a bit of grease on the new pump but I don’t want to risk taking the thing off again now as I might bugger up the rubber seal.

 

But I put a very small bit of grease though on the bottom of the old bolts before installing them so hopefully these won’t weld themselves into the block.

[Vince70]

So I’ve now got a shiny new water pump on and fitted a new belt so I should be ready to go once the new radiator arrives or so you would think but I noticed the new radiator has these extra holes which I presume are for aircon but I just wondered if anyone could tell me for sure.

 

I asked for a non aircon rad and bought this one on eBay but I’m not getting any correspondence from the seller who’s advert stated it was for a non aircon model.

[spike60]

Auto box oil cooler piping?

[The Reverend Bluejeans]

Auto box oil cooler piping?

 

 

Yes. Just ignore them.

 

They are both A/C rads as well, standard ones stop just below the bottom hose outlet. No propbnlem though, just needs an extra litre of coolant.

[Vince70]

Do I have to cap them to stop any coolant escaping

[spike60]

Do I have to cap them to stop any coolant escaping

No, they're for the oil.

[Vince70]

Thanks for that that’s put my mind at rest I can now have a working car this weekend

[DodgeRover]

Electric water pumps....... pffffft.

Ive run one as an auxiliary to get extra heat from the heater for 4 years now, the banger lads use the same pump to cool the engine, have had no problems TBH.

[Dave_Q]

Ah, 4 pot BMW water pumps, what a bastard.

 

Done a couple of those and both times the tab of the housing broke off when trying to wind it out and ended up going full smash on them. 

 

Overall not bad engines, in the end my cooling / water loss issues on the M42 were down to the "profile gasket" which sits between the 2 halves of the rear of the camchain case, and the head has to come off to replace.

[The Reverend Bluejeans]

I've only had 1 BMW pump seize in the block because I did it with a cold engine. Do them with the motor really good and warm, loads of PlusGas, a couple of good slaps on the metal rim with a big hammer and they come out alright. I think my record for an E36 rad is 20 minutes start to finish. 

 

What a well designed cars these were. 

[Vince70]

Cheers Rev.

Mine was stone cold when I did the pump it had been sitting on the drive for a few days so I guess that wouldn’t of helped then.

I’m a bit gutted that I didn’t put a smear of grease on the back of the pump now when I installed the new one and looking at the old pump when it came out it would still of been in perfect condition without the hammer blows lol which surprised me as it’s the original item and the plastic impeller blades looked in perfect condition which I always thought was a weak point on an old Bmw.

I did remember though to give the bearings in the tensioner a nice coating of fresh grease though and it did sound like a mouse was trapped in the engine bay on cold starts occasionally so hopefully that will be cured.

 

But After looking under the bonnet of my fathers a class I’m just glad I’ve not got to do the same job on that thing.

[vaughant]

As per above they are auto trans cooling pipes, I converted my 328i m52 to an iron blocked 325i after countless cooling issues. Despite what the internet might tell you there was no notable difference in performance between the 325 and 328, maybe if you go down the tuning route you start a bit higher but in this day and age I'd drop a bigger capacity engine in rather than try and tune up a M52. We put 80k on it relatively trouble free but the last 20k when it went up to 180k was just untold hassle, constant overheating, would lose coolant for no reason then run fine for a well or so then the same again. Dropped it into a mate* to sort and it was fine for a few weeks then all the problems started again and I was many hundreds or of pocket.

 

Moral of the story, keep on top of older BMW's and a stitch in time saves nine!!!

[Vince70]

I’ve fitted everything back up but can’t start it yet as it looks like ECP has f:(&@£D my order up and hasn’t sent me my 5 litres of blue coolant out.

 

I think I should of left the plastic covers and air filter box off the car to check for any dripping when starting it but hopefully it should be ok.

[Guest VicN]

I’ve fitted everything back up but can’t start it yet as it looks like ECP has f:(&@£D my order up and hasn’t sent me my 5 litres of blue coolant out.

 

I think I should of left the plastic covers and air filter box off the car to check for any dripping when starting it but hopefully it should be ok.

Fill it with water and start it. Then if it leaks you haven't wasted your new coolant.