My Z3 boiled over!.

UK forum for general and technical discussion about the Z3 roadster

Moderator: Gazza

Post Reply
Joined: Mon 08 Jun, 2015 16:41
Posts: 7

  Z3 roadster 1.9i

My Z3 boiled over!.

Post by Peleno2 » Sun 31 Jul, 2016 18:26

Hi, just had the Z3 in for a service last week. I noticed when I got home there was coolant on the drive, but thought it had been overfilled etc.
Took it out for a nice run, on the way home got caught in some queueing traffic. I then noticed temp gauge in the red with the light on!.
Pulled over, let it cool down, then set off again. It came on again after a mile or so, them had to get the AA to bring me home. The AA guy checked several temperatures with his
tool and said that the pipe on one point was 94 degrees, but a few inches away it was 65 degrees. He put it down to a thermostat fault, or the waterpump is faulty and may have lost some of its impellar. I"m taking it back to the garage this week for him to sort it. He did say on the phone that it took 2 litres of coolant to top it up, but thought that because its not been serviced for 12 months it had just lost some.
My questions are: could the radiator be on its way out also, its a 51 plate looks like the original.

Any help appreciated, Cheers, Mark.

Joined: Fri 13 Mar, 2015 09:14
Posts: 831

  Z3 roadster 1.9

Re: My Z3 boiled over!.

Post by mrscalex » Sun 31 Jul, 2016 19:42

I think your mechanic has a fair bit to answer for. If you're saying it needed 2 litres of water at the service there's clearly an issue even over 12 months. For me that's laziness and he should have investigated. That could have been a very expensive problem for you if the engine had got damaged. When the water pump seized on my Alhambra it took the timing belt out and the cylinder head with it. After the repair I had a small amount of coolant loss. The garage brushed it away as normal but I said rubbish as I never used coolant previously. They then found a leak on the cylinder head gasket. Coolant loss happens for a reason!

If the AA mechanic was reporting no coolant loss (was he?) then you have 2 problems at least. Coolant loss and failure of the system to control the temperature. They may be separate issues. The system should be pressure tested for leaks first rather than rush in to a new radiator blind. However it would be of definite benefit to routinely replace the thermostat and water pump. These are not expensive and it should not require a lot of labour charges. Definitely no point dismantling things to check these components and just putting the same ones back if they 'seem/look' okay.

A pressure test will not always show up a slow leak on the cylinder head gasket which is also a possible culprit. But you may be able to see staining from a weep on the block. But if everything else has been ruled out and even if the previous 2 tests on the cylinder head are negative then attention may inevitably turn to the cylinder head. As in the first paragraph it is not always easy to detect.

These are the common issues. I'm sure others may chip in with some of the more subtle causes.
1999 Z3 1.9 Boston Green (Dimitri) - My brother's car owned from new and restored by me
2001 Z3 2.2 Topaz Blue (Trudy) - My car rebuilt from a write-off
2002 Z3 2.2 Titan Silver (Okus) - Project car waiting for a new engine
2001 Z3 2.2 Topaz Blue (Debra) - Donor car/breaker
1998 Z3 1.9 Boston Green (Allsworth) - Donor car/breaker now gone to Z3 heaven
Always happy to try and help with spares :)

Joined: Mon 22 Oct, 2012 18:34
Posts: 205

  Z3 roadster 2.8
Location: Wolverhampton

Re: My Z3 boiled over!.

Post by Lewy » Sun 31 Jul, 2016 21:02

For me if the stat needs replacing I'd do the water pump as well for the nominal cost. Very easy DIY job and the parts are about £60 collectively to do both. If you're anywhere near the Midlands I'll happily help you :)

Sent from my SM-G925F using Tapatalk

Joined: Sun 30 Nov, 2014 22:40
Posts: 306

  Z3 roadster 1.9i

Re: My Z3 boiled over!.

Post by Boosh » Sun 31 Jul, 2016 22:07

I recently had to replace my 1.9 engine, for a suspected head gasket failure revealed more serious issues. As it happened, a faulty relay wouldn't trigger the fan. Temp would however stay in normal operating range as long as the car was moving along, but would overheat at the end of the run, which led to head gasket failure. This coupled with half a stretch bolt swimming under the rocker cover, and bits of the bloc coming off with the water pump. And a hole in the expansion tank had me replace the radiator, too.
All that caused by a relay that probably stopped working before my owning the car. As I would never leave the engine idle after a drive, and the temp gauge would always stay at 12 while driving, I never suspected anything...
It seems your symptoms are fairly similar, though you hopefully won't meet such an expensive outcome.
Fingers crossed, keep us posted,


Post Reply

Who is online

Users browsing this forum: No registered users and 7 guests