Thermostat KV6 2,5....leakage.

[SD1too]

Originally Posted by Typhoon190

This is just my opinion, but I feel there is too much free space in the latest plastic components of the thermostat kit where the o rings sit. They are far too loose across the section diameter which allows movement of the o ring. I also provides too much space for the o ring to collapse into.

If I remember correctly the o ring section is 3.0mm, yet the mould grooves are 4.0mm+

Hi Ben,

During my research I measured a new, genuine 'O' ring (CDU 3858) and your memory serves you well, it was 3.0 mm cross-section sitting in a groove in my original factory thermostat housing 4.0 mm wide and 2.4 mm deep. The 'O' ring therefore protrudes 0.6 mm beyond the housing surface to provide the seal.

I always recommend seeking parts sealed in a labelled MG Rover or X-Part bag for this job. As others have said, there are aftermarket parts sold innocently by reputable and responsible suppliers which are not correct dimensionally. If these are avoided, there should be no problem with the 'O' rings performing properly within their seating.

I agree with you Ben that doing the job according to the manual enables the original parts to be refitted unbroken but with new 'O' rings, thus avoiding the problems raised by using the keyhole method.

Simon

[Azur]

Hello, and thank you all for your reactions! Appreciated and taken into acount.

During investigation where the leak came from, I noticed the following:
Straight pipe: bone dry, both sides, even with the clips not completely at the ends. Inspected with a small telescopic mirror also from underneath in situ.

Actual thermostat housing: dry in the bore connection and at the straight pipe as mentioned before.

Curved pipe: harder to see, looked dry. The actual depth is indeed 2 cm, was in appr. 16 mm.), compared to the depth of the thermostat housing pipe going in the bore (and blocked by plastic components) is 14 mm.

Cooling sensor: seemed wet around the connection with the hole, traces of liquid on the block itself around the sensor...I guess this was the problem.

So, did it again today....keyhole method...(I am a rooky, not looking forward to play around with fuel lines etc. to do with the manifolds)....had to take everything out again. Dried every individual component and measured everything so I can compare later.

Enough is said about the limited space if you use the keyhole method, problem was that I needed to tighten the cooling temp.sensor...and a 22 mm socket spanner is to big to use. Eventually I found a proper tiny adjustable spanner which I could get in and using "invers turning technique", I was able to tighten it properly. Luckely my hands are not that big, otherwhise...


Indeed, if you are able to get the manifolds off, I think the job is more easy, specially to clean everything etc.

Anyway, tested it and it stays dry in the V. So the third attempt worked thank God.

So, my conclusions: first leakage caused by flattened O-rings. Changed the hole thermostat kit OEM from Rimmers. The outcoming thermostat and pipes I will keep as a spare together with new to order O-rings and clips.

Second leakage caused by me not tightening proper enough the coolend temp. sensor. Could have saved myself the neccesary third attempt changing by tightening the sensor enough the second time.

Did I learned something? Yes. Not an easy job for a beginner, but you will learn.
I had all connections (breather pipes, electrics etc.) coloured by tape so I could not go wrong putting things back. Used cable ties to keep the hoses away while working inside the V.

I was able to get the original curved pipe out completely without breaking any parts. I have used a small crowbar with a curved end, which (putted inside the curved pipe) I could lever left and right to get some movement in the curved pipe, followed by prying the plastic pipe in the rounded inner-corner agains the block to lift it up. Patience worked for me here.

Now, next is the ventilator.....that seems not to work...next job but enough done for the last 3 days. Now time to get some proper resting and a good drink.

Cheers and thanks for reading and commenting.

Emiel

[xsport]

Originally Posted by Typhoon190

This is just my opinion, but I feel there is too much free space in the latest plastic components of the thermostat kit where the o rings sit. They are far too loose across the section diameter which allows movement of the o ring. I also provides too much space for the o ring to collapse into.

If I remember correctly the o ring section is 3.0mm, yet the mould grooves are 4.0mm+.

It was a little while back now, but I had a very similar situation when changing the kit on my Dad's 190.

To rectify the issue a purchased some smaller section, slightly smaller diameter o rings to 'pack' the gap inwards and below of the stock o ring.

Hard to explain but hopefully it makes sense?

I would also suggest whilst perhaps a bit more work and cost, removing the upper manifold and at least the front lower inlet manifold gives you much more access and visibility to ensure everything is clean, in suitable condition and aligned properly. Again only my opinion but having tried both methods, the keyhole method is more likely to lead to an issue.

I agree with your comments regarding the sizes of ring to groove measurements. I had exactly the same issues. I am sure that incorrect undersized O rings were sent , or indeed the O rings were old and stretched , as they were already fitted. I did not however measure the rings grooves , which raises an important point.The rings were able to flop around ,both sideways and up and down. Maybe the rings were correct or the grooves were made oversized .. Its a long time ago now , but this was the tipping point for me to try the kaiser stat, and long before simons suggestion of placing the long pipe clips as far apart as possible. I also remember ordering new rings separately , and discarded the ones supplied fitted to the plastic stat. Kaiser has mentioned in the past to not fit rings to thermostats until ready for use, however , on the alloy stat i can understand why. It would not be beyond the realms of possibility that the parts have been altered somewhat , under chinese admin. Or where these parts are now produced .. .. who knows ...

[Arctic]

I am presuming that the stats with the stability pegs are no longer available ? i found these out back in late 2013/early 2014 which i used on my 190 after the original MG ones failed after 18months fitted by Lates.

So i fitted the ones below through keyhole and they lasted for 6yrs and until the car was used has spares.

1

I note that ECP seems to have a photo of them in their listing but am not sure if it's just that a photo, do not know what you receive if purchased.

I've sent a message asking Nick if that is in fact what you receive waiting on an answer.

https://www.ebay.co.uk/itm/132172627840

If it is just that a listing photo then personally i think it needs removing because it is a false alarm for what you may be expecting.