75ZT Community

Well recently on checking my coolant level on my 75 Diesel I discovered lots of oil mixed with water on the header tank cap




Car has done 196, 000, but as failure of head gaskets are unheard of with this engine, surely there has to be another explanation.

Thanks to Arctic for pointing me in the direction of the oil cooler as that is what myself and Steve (Devilish) tackled recently, it sits at the front of the engine and has 1 coolant pipe entering it.


There are 2 gaskets that cab be replaced the one on the oil cooler itself and another that sits behind the cylinder block and the oil filter adapter



First of all had to drain the coolant to find this, where oil had got into the coolant and was forming in globules, note the sludge dripping out of the bottom hose




I then flushed the system first of all with Holts which wasn’t very effective as the oil was still separate from the water and I needed it to mix as there was a lot of sludge at various places including the in line stat which I removed cleaned and have left out for now. So changed to Wynne’s System flush and much better as oil mixed with coolant and came out as one dark liquid.

Next step was to change the oil cooler gasket and had to remove the starter motor to get at one of the oil cooler bolts so put a refurb kit in the starter whilst it was out.

At the time I didn’t change the other gasket as hadn’t got one at that stage and it also looks like one of the bolts to come out is sitting beneath that alternator.

So since then I have kept changing the water and each time there has been less and less oil in it as hopefully the gasket has solved the problem and I am just getting rid of what was already in there, I haven’t yet put any coolant in it until I know I have solved the problem so just running the car at the moment and keeping an eye on the situation.

There are a few historical posts on the forum relating to the oil cooler (John – Number 6 for one ) but not many so please share your experience if you have some knowledge to pass on, and if you have had to do the job did 1 gasket solve the problem or did you need both ?

I will update this thread as and when I make more progress and solve the problem.

I have also had to have a clutch recently but that’s on another thread.

Good post, thanks Rob. Shame you had to have a nasty scare like that in the first place though.

Well I said I would give an update and there have certainly been ups and downs since my last post.

I ran the car and kept flushing and draining the coolant and it got to the stage where I thought it had been sorted as the coolant was starting to look ok, but with my inline stat out the engine was taking an age to get hot and whether the original stat ( which I thought was stuck open ) was closed and then opened I am not sure but went from this



To this in seconds




So I hadn’t solved the problem and it seemed to be worse if anything. I then spoke to a mechanic friend of mine who said it was likely to be the cooler itself as he has changed dozens on various makes of car, so I fitted the used one I had off Arctic and started the flush and draining all over only to get exactly the same result with coolant that was looking to be clear of oil and then at a sudden point when the engine was hot , fresh oil was getting into the header tank.



I then thought I should buy a new cooler but didn’t fancy Rimmers prices at over £100 and looking at the old cooler it is a BMW part and they can be bought for under £50 so I ordered one but at the same time was thinking I had my own cooler on and then replaced it with another used one and got exactly the same result with oil in the header tank and the used one off Arctic came off a car without any of the same issues so started to think it wasnt the cooler after all

So the only thing I hadn’t changed was the second gasket known as the cylinder block to oil filter adapter gasket which I now had



There are 3 bolts to remove as on Arctic's pictures on this thread but with the engine in situ one of them sits behind the alternator which looks as though it would have to be removed and to do that I might have had to also remove the air con compressor and without access to a lift we decided to take off the front end to access as the front end is something we are more used to removing ands it is a much more comfortable working position than lying under the car





With the clylinder block adapter removed this is what you see




The old gasket was inspected in place and seemed to have flattened off and was allowing oil to pass through into the coolant chamber on the right




New gasket compared to old one and cylinder block adapter refitted to car and the front end reassembled

More flushing and draining and all seems good, I have refit my 92 degree in line stat and engine has reached those temperatures but so far no sign of any more oil in the header tank, so coolant added and will keep an eye on things over next few days.

It’s a difficult task changing the cylinder block gasket but that was obviously the cause of oil getting into the water so if it happens to you my advice would be change both gaskets and the oil cooler. I still have the used cooler fitted but the new one will arrive tomorrow so will keep it on the shelf and hope it never gets used, but if it is needed it can be changed after removal of the starter motor so not too bad a job to tackle.

So with the cooler issue solved and a new clutch in last week too, I am hoping to add to the 196,000 miles and head on towards moon club membership


Big thanks again to Arctic and Devilish for their help with this

Well done guys.

As Duncan says, well done, not a job I'd fancy doing, so I hope it doesn't occur otherwise it might be bye bye Rover! I've still got to get round to finding out why my battery charge light stays on, albeit a bit dimmer, after I had the alternator changed, got to take the bumper off to check wiring on the front from the fbh sensor for chafing. Always seem to struggle getting the bumper off and on so it'll have to wait for warmer weather as the alternator is charging ok.

Martyn

Hi Rob.
A few weeks have passed now how is the girl running, i now she as also had a crank pulley done in the mean time, but is the oil situation completely curd now, are you going to give her another coolant change in the new year.

All good Steve, no intention to reflush it as it was done to death and the heat in the cabin comes through quicker than ever now even without the FBH (Fuel burning heater.) so i just keep an eye on the header tank and cap.

Not had much luck of late though, new clutch with DMF, Oil Cooler, Crank Pulley and had a puncture on Christmas Eve when one of the undertray bolts dropped out and went straight into the nearside rear tyre, I was close to National Tyres in Cannock so took it straight there and was told it would be a 45 minute wait, so sat in car and waited and check the on line National Tyre price of a like for like Avon S7 which was £65 fully fitted. I was seen after about an hour and the guy who was looking after me spent more time running back into the office to sort other issues out than checking out my tyre, of course it was not repairable so a new tyre was needed, he then spent the rest of the time holding a mobile phone between his shoulder and ear having a long personal call with one of his mates and when he came to put the tyre back on I had to remind him that he hadn't balanced it,good job I watched him while he was " working ". Anyway tyre fitted and into the office to pay, "ok that will be £103", so I reminded him of the on line price and he said it couldn't be sold for that much unless ordered on line, to which I replied I could have ordered it online during the hour I had spent waiting to be seen, and he said you could have but it wouldn't have been fitted today as you have to book a slot, to which I replied well you had available slots as you have just fitted me a new tyre without any appointment. He said it happens all the time with the online and just turn up prices and nothing he could do and I said its the same tyre sold by the same company so why should there be any difference at all.

Anyway after more heated debate I asked for a discount and I settled on £83 which was still more than the online £65 but £20 less than the £103 asking price and a 20% discount. I checked the undertray when I got home and both rear bolts were missing and it is currently held up with extra strong tie grips as a temporary measure.

Rob hopefully 2021 will see you have trouble free motoring, happy new Year.

Thanks Steve and a Happy New Year to you and Gail too, looking forward to getting rid of Covid and plenty of car meets

Trebor wrote:looking forward to getting rid of [...] plenty of car meets

Happy new year!

Trebor wrote:Thanks Steve and a Happy New Year to you and Gail too,

looking forward to getting rid of Covid

and plenty of car meets

Rob when & where did you catch it, how long will it take you to get rid of it.

Thankfully it has not got me yet and hope it stays that way !