E34 518i

Post Sat Oct 22, 2011 6:00 pm

are M43 heads prone to cracking?

just bought a nice 1994 518i (M43 engine) from a dealer about 25 miles from my house (with no warranty), it seemed a solid enough car and was driving beautifully until 5 miles from my house the top hose blew off and it dropped all the coolant. it seems that the plastic pipe on the rad had cracked and the remains of it were in the top hose. fortunately i spotted the temp going up and turned it off just before it got into the red.
i let it cool by the side of the road and my mate came to the rescue with a barrel of water. we topped it up and attempted to bleed it up a bit at the side of the road but it just kept blowing water out of the top of the filler neck as if the system was being pressurised.

i'm fairly sure this is headgasket failure or a cracked head. i need to know if the m43 heads are prone to cracking so i can decide what to do i.e. negotiating for some of my money back and keep the car or all of my money back and give the car back. it would be a shame if i had to give it back as it's a lovely car that drives a lot nicer than any of my other beemers. i'm capable of fixing it myself and would rather know it's been done properly myself than have them do it on the cheap (if they offer to fix it) i.e. not skim the head etc.

i called the dealer and he said bring it back so his guys can have a look at it; i'm taking it back to the dealer tomorrow.

also if anyone knows of any areas of the headgasket that are prone to failure that may be helpful.

Post Sat Oct 22, 2011 8:37 pm

As you've literally just bought it from a dealer they have to offer some sort of warranty and either fix it or refund you. If you'd bought it privately you wouldnt have a leg to stand on.

I had cooling system issues with my last E36 I bought from a dealer - ended up costing them a genuine BMW radiator, Water pump and thermostat - which was probably all the profit they made on the car !

Let the dealer sort it out - less hassle for you and if they fix it they have to guarantee the work.

Post Sat Oct 22, 2011 8:59 pm

water pump mate, they come with a plastic blade fitted which ends up cracking and coming off the spindle, whole system pressurises cracks rad etc, 15 min- hour depending on skills to remove water pump and check, you'll prob find that the problem! had same problem with my m50, i also drive a 518 1994 as my daily driver,

when you buy a new pump make sure it a metal end one.

quick guide done on doing my m50 pump you will see what i mean bout the plastic finned pump

sure it same prob with the 1.8

http://forum.bmw5.co.uk/topic/42426-rep ... msearch__1

Post Sat Oct 22, 2011 11:00 pm

M43s are lovely little donks but head gasket failure is their one problem area. BMW didn't fit them with a coolant level sensor. They're quite an easy fix though.

Post Sun Oct 23, 2011 9:49 am

alan1272 wrote: (with no warranty)

There you go. Sale of Goods act be damned, you cannot guarantee a 15+ year old car for 5 minutes, never mind 3/6 months. I'm surprised a dealer even entertained it.
M43 heads rarely crack - a skim, gasket and bolts will sort it along with a pump and a used rad.

Post Sun Oct 23, 2011 10:57 am

cheers guys, taking it back today. the guy seemed ok on the phone and they're a fairly reputable independant bmw dealer so hopefully they'll play ball.

best place to get a metal finned water pump? ecp? gsf?

Post Sun Oct 23, 2011 11:49 am

If you're going to fix it yourself get a KWP pump from ECP - collect it in person and open the box before you leave the shop to make sure though.

Post Sun Oct 23, 2011 3:52 pm

well i limped it back 20 miles with no problems. kept the revs low and made sure i didn't put it under much load, this makes me think that its going to be the head gasket as it had originally failed when under heavy load up a hill.

dealer was very apologetic and asked me to contact him tomorrow.

what i don't particularly want is for them to offer to fix it because for what i paid for the car, they'd be making a loss on doing a proper job of it, and that makes me think that they'll just bodge it to get it gone.

anyone know what an E34 goes for on the weighbridge so i can just offer him that much for it?

Post Sun Oct 23, 2011 4:54 pm

get bout 200-250 i reckon, maybe more.

Post Mon Oct 24, 2011 12:16 pm

ok just been on the phone to them and they're claiming it was just the rad that was the problem. the mechanic spoke to me and said " the plastics degrade and thats why the pipe on the rad broke off." so they are replacing the rad.
i said to him i believe it was pressurising and he claimed there was just an air lock in the system.

anyone heard of this issue with the plastics on the radiators?
i find it slightly suspicious that it let go when going up a hill, i.e. under most load.

Post Mon Oct 24, 2011 1:22 pm

Well to be fair the plastic housings do break so I see no reason why the rad wouldn't suffer the same fate, I did an un neccesary head gasket replacement on my E36 316i compact (M43B19TU), it was a horrid thing to bleed, in the end I used a vacum filler and it got rid of the airlock first time, I also replaced the water pump again un neccesarily, the genuine plastic impeller pump with 160,000 miles on it was perfect.

Post Fri Nov 04, 2011 7:29 pm

just to conclude this; it appears to have just been the radiator that had gone brittle. once all the airlocks were out of the system and with a new rad fitted it's been fine.

Post Sun Nov 06, 2011 9:51 pm

great news, enjoy the car