Rover 75 2.5 V6 Con water leak question

[Snarfz]

Hello again!

Ok so I went to the garage to get some clarification, and there were more issues than I thought. Hopefully anyone here can give me some insight.

So the leakage from the hose under the cooling tank was easy to fix, but there seem to be more leakages.

See picture one for the leakage under the motor on the left side. They believe its the big hose going underneath the motor (which is the hard one to change).

Check picture one for the hoses which are going underneath. The small one seem to be circulating fine since it was getting hot quite fast. We left the car on for about 10min (the motor got hot fast and the vent turned on pretty fast). The big tube on the other hand wasn’t getting hot and doesn’t seem to be circulating well. We also opened the cap to check for any airlocks but the agent was leaking from the cap fine.

They think it’s still the thermostat not opening correctly which is causing this, which also caused the tube to break because of the pressure. The car is from 2002 but has only 20 000km, so it has been standing in the garage for a long time.

They said that it wouldnt be an easy/fast job to check the parts and that’s why they gave the cost noted above.

Does this sound like a valid analysis?

Picture 1 : https://imgur.com/a/lpX8ZnA
(I have marked the area where the cooling agent is accumulating).

Picture 2 : https://imgur.com/a/OIICRmJ

Thank you in advance for any respones!
Franz

[SD1too]

Originally Posted by Snarfz

They think it’s still the thermostat not opening correctly which is causing this ...

Thanks for photo no. 2 which is very helpful and I agree with the diagnosis. You have no flow through your radiator. But I am puzzled by the large hose third from the left being cold. That should be red hot.

Originally Posted by Snarfz

See picture one for the leakage under the motor on the left side.

Nothing's visible in picture one I'm afraid Franz.

There are two possibilities here:

1. The thermostat isn't opening, causing overheating. This is very rare but it can happen.
2. Someone has put K-Seal into the cooling system which is known to cause unpredictable and variable effects. It is also extremely difficult to remove.

Simon

[Snarfz]

Hello Simon!

Thanks again for the fast response.

Yeah both of the big ones after 10 mins of running the car were getting just a tiny bit of warm, while the small ones were red hot.

Sorry about the first photo, that's why I marked the area, it's very hard to see, but there is basically a pool of coolant just where the mark is. If you look very close at the dark area inside the yellow mark you can see a very vague white dot, that's basically a reflection of the coolant, that's the best I got.
But they said that there is a leakage from the big hose going under there, and will have to open up everything to change it etc.

Thanks for the ideas, if those are the possibilities then I'll probably have to go through and open it up to check. I was hoping it was something more simple.

A question, so to get to the thermostat and check the flow of the hose and for leakages etc is a 2 day job on this car then? (sorry I really have no idea how complicated etc these things are). We negotiated a bit and they said they could do only the service for minimum 500€.

Franz

[SD1too]

Originally Posted by Snarfz

Yeah both of the big ones after 10 mins of running the car were getting just a tiny bit of warm, while the small ones were red hot.

The small hose on the far right hand side of your photo is the heater return. It is the same hose shown third from the right in your photo which leads back to the engine block. It makes sense that these are hot.

The large hose (second from the right, in between the small hoses) is the flow from the block via the curved pipe to the top of the radiator. If the major leak from the expansion tank has been repaired and the coolant level is correct then this large hose should be hot.

The large hose on the far left hand side is the return from the bottom of the radiator via the oil cooler and bleed screw to the thermostat. When the thermostat opens this hose will also feel hot.

All testing should be carried out with the cooling system refilled according to the MG Rover procedure which involves raising the expansion tank and using the bleed screw. Does your garage know about this? If not, it's highly likely that air locks have been introduced which could explain the cold hoses. You can find the procedure in detail by searching under my user name.

Originally Posted by Snarfz

Sorry about the first photo ... it's very hard to see ... they said that there is a leakage from the big hose going under there ...

The only hose in that vicinity is the flow from block to heater.

Simon

[Snarfz]

Hi Simon,

Thank you for the detailed explanation, I learned a lot!

Originally Posted by SD1too

All testing should be carried out with the cooling system refilled according to the MG Rover procedure which involves raising the expansion tank and using the bleed screw. Does your garage know about this? If not, it's highly likely that air locks have been introduced which could explain the cold hoses. You can find the procedure in detail by searching under my user name.

The only hose in that vicinity is the flow from block to heater.

Simon

Yes everything was refilled and topped up, we tried to open the bleed screw and it was normal, no airlocks.
I went through with the service, they will open it up and check everything. Will come back when I know more.

Thanks!

[Snarfz]

Hello again,

Ok so they removed the thermostat (see picture) and wants to replace it. Is there a way to test if it is working properly? If so please advice.
Also does the whole thing they are holding need to be replaced?

https://imgur.com/a/PivTLce

Thanks,
Franz

[Popcorn]

Not sure as I have a diesel,but Dmgr list these https://www.dmgrs.co.uk/search?q=kv6...+&type=product
Usual way to test a thermostat is put it in boiling water and watch it open or not open ,if your stat is sealed in it's housing may be a bit difficult, sure the petrol owners will be able to tell you more

[Snarfz]

Originally Posted by Popcorn

Not sure as I have a diesel,but Dmgr list these https://www.dmgrs.co.uk/search?q=kv6...+&type=product
Usual way to test a thermostat is put it in boiling water and watch it open or not open ,if your stat is sealed in it's housing may be a bit difficult, sure the petrol owners will be able to tell you more

Hello,

Will check if this works thanks.

I also notices they have used glue or silicone at the ends to seal it better, this is is normal?

https://imgur.com/a/xlpj6zp

Thanks,
Franz

[SD1too]

Originally Posted by Snarfz

Ok so they removed the thermostat (see picture) and wants to replace it. Is there a way to test if it is working properly? ...
Also does the whole thing they are holding need to be replaced?

First disconnect the straight pipe from the thermostat housing (it would normally pull out but judging by your later photo some bodgery has taken place).
Next place it in a pan of cold water with a thermometer. Make sure that the bulb or probe is close to the base of the metal thermostat and not touching the pan's metalwork.
Now heat the water and when it reaches about 80˚C watch the thermostat's circular plate carefully. At about 88˚C you should see this slowly opening (the gap is smaller than you might think). The plate should continue to move until about 96˚C is reached.

If you simply drop the thermostat into boiling water (as suggested above) you won't know whether it is opening at the correct temperature. The thermometer method is much more accurate and informative.

Originally Posted by Snarfz

I also notice they have used glue or silicone at the ends to seal it better, this is is normal?

No, it's neither normal nor necessary. What a bodge!
You can see in your photograph that the 'O' ring seal is severely flattened. That is the cause of the leak and it's happened because the serrated clips haven't been set properly.

In view of the condition of the parts you have photographed I recommend that you renew all three plastic sections: the curved pipe, the thermostat housing and the straight pipe. Assemble these with the serrated clips loose then, when everything is seated properly, move the clips outwards so that they are touching the water pump inlet and thermostat housing. Now squeeze the jaws together so that the clips cannot move. Do not use any sealant or glue.

Beware of unbranded pattern parts on eBay. Correct dimensions are critical for a reliable seal. Your best source is direct from Motaclan in the UK or an official supplier such as E Car Parts. There's also DMGRS and Rimmer Bros. who post internationally.

Simon