VR6 coolant leak - new parts and still leaking!

[dghodges 0]

Looking for a bit of advice please folks.

 

I've got a coolant leak on my '93 VR. Its from the flange on the top right of the radiator (if standing in front of car looking at it). It appears to be where the flange meets the radiator. I say appears to be as I can never see it leaking, only the evidence after a spirited drive (water on the slam panel and down the side of the passenger wing).

 

I have changed the plastic flange as the old one had a split next to the front bolt and had gone quite brittle. I have also changed the O-ring with the correct VW part. I have made sure that the plastic part of the radiator it pushes into was in good condition with no scoring or damage, all seems in good condition BUT IS STILL LEAKING! I've even tried a slightly thicker o-ring to provide an even tighter seal and it still leaks.

 

I'm really looking to see what approach others would take now. Could my system be over pressurising? What would cause this? Coolant and oil temps seem normal, 85 C and approx 100 C respectively. I am going to swap the expansion cap for one off my valver and see if this helps. Should the cap have to release pressure normally or would it point to there being another problem?

 

Any help/advice gratefully received.

 

Dave

[toledo 0]

You replaced the flange with a brand new VW one ?

[Dude VR6 0]

Fire the car up and let is come up to temp, and wait for the fans to kick in. Have a look around the area and see if you can see any thing, it maybe the hose has a small hole in it.

[dghodges 0]

Right, had another nose around quickly this morning and realised the auxiliary water pump is working intermittently. It has always been very noisy, well at least in the 2 years i've had it it has been. Presumably this could be stopping the coolant flowing as freely and pressurizing certain sections of the system.

 

toledo Yep it was a brand spanking new VW flange and o-ring.

 

Dude VR6 I've had a look quite a few times for actual leaking, even about 20 seconds after seeing steam from the front of the bonnet and the engine still running, but can't see anything, just puddles on the slam panel etc from when its been leaking when i've been driving :-s

[dghodges 0]

Got a new aux pump today, ended up going for a cr@ppy GSF one (still £94 quid). Only took half an hour to remove and fit so won't be too much of a hassle to take it back if i have any problems. Having now seen the design of the pump I don't think it has any bearing on my current coolant leak. Tomorrow I will be unplugging the fan to see if the extra heat will pressurize the system enough for me to see where it is leaking. Really want to get to the bottom of this as I think its getting worse. I'm not sure now that it is leaking from the flange that I replaced. Its still pooling on the slam panel but that could be from the radiator. Oh well, I'll keep searching :)

[dghodges 0]

Well found a leak, top right of the radiator. It could have been this right from the start and not the flange, although the old flange was cracked due to a rusty bolt and was very brittle, obviously seeing better days. I still couldn't see the leak under normal circumstances. After unplugging the fan and letting the coolant get up to around 105C I could see the leak. Another added benefit of this is I now know the fan works at at least one faster speed, as when plugged back in there was some serious air being moved :) I don't really want to buy a new rad so I have tried a £10 bottle of K-seal (first time I've used any sort of additive so a little sceptical). I should find out tomorrow if it has worked or not. Fingers crossed!

[Critical_Mass 10]

funnily enough i have the same issue. Looks like the seal has gone and its leaking, doesnt look to be much but the level drops quickly. Went shopping yesterday and came back to the car in the car park with a big patch of wet on the floor. been carrying a gallon of water in the boot.

 

I tried some rad seal but it hasnt really worked. Gonna try get a seal next week.

[Roger Blassberg 0]

Other sources of leaking water in that area are the small hoses to/from the oil/water heat exchanger above the oil filter and the various plastic parts and o-rings around the thermostat and transfer pipe.

To be honest, I would not put radiator sealant into the system; some of the waterways are barely adequately sized even at the best of times and any further restriction is not going to be in your long-term interests.

 

Best wishes

 

RB

[dghodges 0]

Well no signs of any leaks today. I'm going to leave it until the weekend before I get too excited. I'm thinking that I will flush the coolant system to get any unused k-seal out and to put new G12+ in as it is mostly water at the mo. I'm not entirely sure how this k-seal works but I'm assuming that once the leak is fixed it should remain so, even if I flush the system. If anyone knows it would be good to hear. cheers

[Critical_Mass 10]

Well after i replaced the flange and O ring on my rad, today the radiator decided to spring a leak. Fcking CAR!!!! grrrrrr