My Diesel 75 is loosing coolant

[alanaslan]

Originally Posted by alanaslan

Hi Simon, she only reached 104 degrees when she was low in coolant. Also the fan was running at high speed. ( thanks Jules your new fan works a treat.)
The reason for me fitting a second stat was the new stat was either failing to close properly or the stat was opening far to early.
A common problem I know. The engines own stat was open at 70 degrees three months after fitting. Had a choice of two guess I picked the wrong one. They were both brand new and still in their packaging. For this reason I made up an inline stat casing to fit in conjunction with the cars own stat. Since fitting this unit the car is running at the correct temperature checked both;by the cars OBD2 information. And from checking with my temp gun which is in calibration.
The difference is fantastic before fitting my new inline stat the car was getting 30.4 mpg. With the unit fitted she is now getting 35.3.
Just what the doctor ordered, when towing I select sports drive and she tows the Caravan with ease. Yes she is a 158Bhp Diesel, pulling the van in sports drive I find keeps the engine on cam with the turbo running nicely to give instant boost as required. With her in drive I find she has to change down to get the required boost. You could almost describe the feeling that she was pinking, I know she is a diesel just trying to describe the feeling. As she has the torque to easily pull the van with out being lumpy I just select sports mode and the slight lift in rpm by her being held in the lower gear for the extra 300 rpm makes all the difference.
Jules will send you the stuff in the morning.
Kind regards to all
Alan


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The new Rover thermostat has been leaking at its rubber seal, this is the one that is opening early, I have replaced it with the other new thermostat that I had on the shelf. Since doing this I have covered five hundred car miles and one hundred and sixty Caravan miles. Have been checking the water level daily, and am happy to confirm no water consumption, removed the in-line stat yesterday with a new top hose will now run her for a thousand miles and if all is well I’ll drain her down and fill with -40 protection antifreeze mix hopefully there will still be no leaks.
Alan


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[alanaslan]

Originally Posted by Jules

Well if it's any cosolation Alan I've only heard of 2 cases of HGF pressurisation with the CDT (both behaved unless towing!)



The only other important thing to point out is the Renault 5 inline stat a lot of owners fit is NOT suitable for towing on hot days. (think yours is OEM)



The "Precision Engineering" inline type is fine.



Have you monitored the coolant temp via the built in OBD dash test no 7?

Hi Jules, thought I would let you know that I traced the coolant leak down to the rubber seal on the thermostat housing. Fitted last October fresh from the bag. I should have guessed as the stat had got lazy very quickly.
I still have to confess that I don’t know the exact conditions under which that it was leaking. However was fortunate enough to open the bonnet to have a check just as it was doing it, things were not that hot at the time so I am surprised by its failure.
I have now fitted the other spare that I had on the shelf this time coating all rubber seals in silicone PTFE grease ( used to use it when assembling the fire pumps in flats that were in my charge before I retired. ) I am convinced that these buildings were only added to my remit as my team and myself all had excellent engineering skills, along with working on some very strange and somewhat unique equipment over a combined century of experience between the three of us. Our two boys both went on to work for large filtration companies after they had served their time.
Two weeks now with no leeks except the NSFront sun roof drain.
Have today taped up the roof and hydro extracted the carpets just to make sure that it is the drain, as it has been a constant pain with my Tourer. If the coolant system holds up for another two weeks with no more problems. Then I will drain her down and refill with the pink stuff offering protection down to minus 40, hopefully the added mixture will not find anymore leeks.
So I now find myself with no spare water pumps on the shelf but a full size coolant radiator To go with the AC rad and the intercooler rads already on the shelf, along with every hose except the top radiator hose as I removed the inline stat when fitting the the other new OEM one.
Jules many thanks again for all the advice, if we ever get to meet up I must buy you a bottle. It is so nice to have someone out there who has experience with our cars and is willing to share that experience with other club members.
Kind regards
Alan


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[Jules]

No problem Alan

The problem with OEM stat housings if bought in the last 5 years is they are not OEM but pattern!

They have a shiny appearance with no markings on whereas the originals had a mottled finish with BMW stamp and "made in Austria" which have sadly been obsolete for a while.
The pattern seals are inferior too and we've annoyingly had a couple leak out of the box !!

[T16]

What is the BMW part number for the proper stat, over the garbage that Xpart will have conjured up.

[Jules]

Originally Posted by T16

What is the BMW part number for the proper stat, over the garbage that Xpart will have conjured up.

They are obsolete.
Xpart found the next alternatative

[T-Cut]

Originally Posted by T16

What is the BMW part number for the proper stat,

Maybe this shows it?




TC