What do i do :( at my wits end with my Z3.

[Lums123]

Hello Roadsters. im Looking for some advice on what i should do with my Z3 that seems to have a blown head gasket or possibly (hopefully lol) something else.

I Purchased my 2001 Z3 1.9 4cyl in June/July 2023. I took a risk buying the car as it was registered as cat D but i loved the look of it and it was within my budget for a convertible. After owning the car for around 2 months i immediately got the tracking done as it was all over the place over 50mph. i was told it may possibly have a bent/damaged control arms. from the get go i knew it needed new tyres also as two on the front were odd profile and the rears were super wide for the car as the person i bought the Z3 from had installed 18in 9J wheels on the rear.

eventually i snapped a spring which led me to replace all 4 springs with Eibach 30mm lowering springs. upon installing i noticed that the car had 3 lowered springs on and one stock height spring lol so yeah frustrating and slowly realised id been sold a pretty bodged up Z3.

A week after replacing the springs i had a overheating problem somewhere. i replaced the thermostat then the water pump then expansion tank which was impossible to get one that fitted so in the end bought a whole new radiator. it took ages before she was running again. over winter i purchased a lovely set of 18in AC Schnitzer wheels from a enthusiast on here! Was super happy with how the looked on the car.

at last the Z3 was driving again and fun times were had for all of about 4 months. the next problem was the bonnet lever had broken. i imagine the lever was broken for about 2 months before i noticed it. once i did notice it i started driving it less until my mechanic could fit me in as i didn't want to run the risk of no oil or coolant. by the time my mechanic fitted my in the week before the engine light came on when i started it. i immediately turnt it off and the next time i drove it was to the garage which it then over heated.

LONG STORY SHORT
My mechanic fixed the bonnet lever and said he ended up putting almost 4L of coolant in which isn't good. the oil level was fine he said. he replaced the rocker cover as it wasn't installed the best and said there was a tiny tiny bit of oil mixed in with coolant which could mean a head gasket being gone. we agreed on using a bottle of steel seal head gasket sealer in trying to prolong the head gasket if it was going to go.

A week later i got my Z3 back after my mechanic had gave it the all clear. he had it running for over 3 hours after leaving it over the weekend for the gasket sealer to do its thing. he said the fan kicked in when leaving it to run and he also drove it for a half hour and it drove great. (also a slight problem the fan seems to not kick in or be very temperamental)

i got it back and it felt great until it started overheating again. this time was slightly different. the temp gauge went over the red but there was very little smoke/steam.
i pulled over as soon as i could and investigated. strangely the front of the radiator was very cold which i have never had before. its normally very hot at the front. it was warm in front of the fan and also there was what looks like a explosion of coolant fro the expansion tank (pics attached)

Now when i start it up and leave it running it is fine for about 10 minutes and the the water in expansion tank rises, temp gauge goes up and eventually starts leaking coolant out of the expansion tank.

Which now leaves me stuck as my mechanic is confused himself as he had it going fine and says it could still be the head gasket he did suggest trying to remove the system in the thermostat but for now i have given up feeling v hopeless and that inevitably its looking like i get rid of the car in parts or scrap. OR fork out for a new head gasket

BASICALLY WHAT IM ASKING.
what do i do? does this sound like a definite blown head gasket? could it be something else? has anyone had there Z3 go through a similar thing? do i fork out and replace the head gasket is or isit such a job its not even worth it for this little 1.9 Z3.

Im currently tempted to take the good wheels off and get rid of it in parts or break it down and cut my losses.

I bought the Car for £2.2k and probably spent £1000 in replacing parts and other mods. the wheels were around £800.

Id really appreciate any advice on what to do as now the Z is just sadly parked on the drive.

Many thanks

Tyla

 

[Nodzed]

Get yourself a head gasket leak test kit, they are around £35 (ish) from Amazon or elsewhere. This will check for exhaust gases in the coolant and simple to use. It will be cheaper and easier than spending more money on a garage to diagnose.

If the HG has gone sealant wont work especially long term, and it pretty much sounds as if it may have gone. But it looks a nice Zed so dont give up on it yet.

 

[Synclare]

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[Pond]

Now when i start it up and leave it running it is fine for about 10 minutes and the the water in expansion tank rises, temp gauge goes up and eventually starts leaking coolant out of the expansion tank.

That is an airlock somewhere in the coolant system. The ten minutes is when the thermostat is opening, but the coolant can't circulate, so easiest path is back to the expansion tank. The expansion tank can't hold all the coolant so it overflows. The clue is that it ran dry (almost) as you said your mechanic put 4 litres in. He obviously didn't bleed it (properly).

The problem can perpetuate, as when the coolant overflows, the expansion tank will drain, causing more air to be 'sucked' into the coolant system.
I spent 3 days sorting this exact same problem on my daughter's car very recently.

If there is significant oil in the coolant (brown sludge) and/or significant 'mayonnaise' in the oil (inside oil filler cap best place to see it) then it could be HG aswell.

I would find a better mechanic, aswell!

 

[Devon Z]

Really nice example, great colour combination and sits nice on the AC’s.

Stick with it if you can I’ve seen worse put back on the road.

 

[Andyboy]

M43's are prone to head gasket drama for whatever reason. The head will be warped as well. They rarely crack.

But: It's not the end of the world. The M43 has an iron block which is pretty resilient so no pulled block threads when you torque up the head bolts.


But.........

One last roll of the dice! It may well be that the electric fan is NFG. These are pretty simple with power, earth and two power wires for fan speed, fast and slow. I'd be tempted to bridge the sensor connector to have it on slow permanently and see how you go. If it behaves, that's it. Anything under 30 mph and you really need a fan. If it's acting up around town and slow traffic, a faulty fan will certainly cause overheating.

Older non air conditioned cars (96-99 M44) have a mechanical viscous coupled fan and a plastic shroud. That's about £50 in used parts, £40 for a new coupling and about 40 minutes work to fit, replacing the electric fan. If your car has aircon that works, then you do need the electric fan.

But really, my gut feeling is the head gasket. About £1000 to fix. Four hours to get the head off, a skim and pressure test is about £100, reassemble plus a gasket set and new heads bolts.

Bleeding BMW cooling systems is not the drama it's purported to be. Bleed screw out, on idle with heater set to hot and slowly add coolant until it starts to run out of the bleed screw hole. The emphasis is on 'slowly'. When the heater is blowing hot air, it's done.