Coolant Leak

[Solitaire 0]

Can anyone help with the following problem, a couple of months ago the coolant warning light would intermittently flash, on one occassion only, the level was low, therefore, i changed the coolant bottle/sensor, the problem is still there, but now the level is regularly dropping, tho not completely emptying the coolant, it seems to drop so far, then stop, i have suspected the head gasket, as there is an intermittent misfire, but no other signs, and the misfire could be due to a faulty plug or lead as the car is due a service. Dont want to start panicking if it could be something simple the car is a VR6 with 112,000 miles, full service history, there is no water in oil or vice versa, and it has no starting problems, or overheating.

 

please help with some suggestions of what to check, thanks

[Kevin Bacon 5]

Blimey, where to begin? The VR is notorious for coolant problems.

 

Mine did exactly as you describe and it turned out to be a duff thermostat that was intermittently jamming shut. The coolant level would be fine for a while, then it would spit loads out of the expansion tank (look for water marks around there) and then level off again.

 

I changed out the thermostat and it's been fine ever since.

 

The VR6 coolant system is quite complex & troublesome. It consists of twin two speed fans, an electric aux pump that activates at 107 degrees and when the igntion is on plus on the after-run program. These pumps are prone to failure and leaks. It's next to the coil pack. You should hear it whirring with the ignition on (engine off).

 

Are there any obvious coolant leaks? Does the fluid in the expansion tank smell of exhaust gases?

 

Kev

[Solitaire 0]

Cheers for the advice kev, but am still stuck, this morning i checked the coolant level, which was very slightly below minimum, there was no water marks around the top of the tank, and after topping the level up to maximum, the coolant warning sensor was flashing! dont know why, because as i said previously, this is a new sensor as i originally believed the sensor to be faulty. Anyway, 20 minutes into the journey, it stopped flashing. I checked for any smell in the coolant tank and it doesnt really smell of anything. Also can see no trace of leaks anywhere. A friend has suggested it may be a leaking hose, or radiator, but it is such a small leak, i'll top up from just below min, to max, about once every couple of weeks. Need to get it sorted pretty quick really, as i was after a blackberry car and there is one available at the mo in reading, so mine could very well be up for sale.

 

Also, if anyone on the forum knows the reading car, would appreciate some info, its advertised in autotrader this week, and steve, the owner, says he has owned it for about 3 months, its a 96N VR6, blackberry with Grey leather, and 37000 miles, sorry its a little short on info will add if i get any more.

 

cheers

[vr6storm 0]

Cheers for the advice kev, but am still stuck, this morning i checked the coolant level, which was very slightly below minimum, there was no water marks around the top of the tank, and after topping the level up to maximum, the coolant warning sensor was flashing! dont know why, because as i said previously, this is a new sensor as i originally believed the sensor to be faulty. Anyway, 20 minutes into the journey, it stopped flashing. I checked for any smell in the coolant tank and it doesnt really smell of anything. Also can see no trace of leaks anywhere. A friend has suggested it may be a leaking hose, or radiator, but it is such a small leak, i'll top up from just below min, to max, about once every couple of weeks. Need to get it sorted pretty quick really, as i was after a blackberry car and there is one available at the mo in reading, so mine could very well be up for sale.

 

Also, if anyone on the forum knows the reading car, would appreciate some info, its advertised in autotrader this week, and steve, the owner, says he has owned it for about 3 months, its a 96N VR6, blackberry with Grey leather, and 37000 miles, sorry its a little short on info will add if i get any more.

 

cheers

 

 

have you tried the expansion tank cap?........as the seal might be knack'd and when the coolant is getting hot a little bit might be escaping

 

 

on another note this "37k" mile VR6 sounds to me to be a little bit suspect,as most people try and keep hold of "low-mile" VR6 for longer than 3 months.............i'm sure the vendor might have a very valid reason for selling.....but i would be extra vigilant if i were you.........don't take "seeing" service history that "validates" the mileage......get its chassis number and PHONE VW's Customer service and get them to check when it was last VW serviced

[Solitaire 0]

Cheers Rodders,

 

Will give that a go, have had the car 'combustion tested' today to check the head gasket and that has come back negative, however, the mechanic says there is another test he can do later in the week, but he believes the head gasket is ok, will check out the expansion tank cap and see if it looks ok.

 

Also cheers on the blackberry VR6, but i dont think i'll be going to see it afterall, as the vehicle is on Cat D on HPI, and at £7650, i would be looking for one which is A1, looks like i'll be keeping my black one for a little longer, give me a bit more time to sort out the problem.

 

Regards, caroline

[Solitaire 0]

Thought i give this a push up the list as i still have a problem

 

My garage has pressure tested the system for me today, and cannot find a leak, although they do agree the system is leaking, they have done me a favour by checking it out as they try not to do corrado's but i have been taking my cars to them for years (and VW are so much more expensive!). Anyway, they say there are rust marks down the front of the engine, but they cannot see the source of the leak, they also did me another favour, and combustion tested it again just to be sure, and they say it is definately NOT the head gasket.

 

As they dont have much experience of Corrado's thought you lot might be the best bet again, any ideas?, would anyone happen to have a diagram of the front of the engine, poss on .pdf, so i could get any thoughts on where the leak may be.

 

I am sure this cuts out the water pump, as isnt that on the side of the engine?, and i have dismissed the coolant bottle/top aswell, as these are now new.

 

I was in a small accident in this car just before i noticed the problems, and the engine did bounce in the accident, enough to blow the rear engine mounting, so just wondering if i could have loosened anything off, there was no major damage to the car otherwise.

 

Any suggestions welcomed!, cheers caroline

[Kevin Bacon 5]

It might be the thermostat housing. If it seeps (usually when under pressure), it can drip round to the front of the block. There is also a plastic water transfer pipe that travels from the pump to the stat housing (sits above the oil filter housing). Check that for hairline cracks.

 

If the water pump has gone, it'll drip a puddle on the floor under the pulleys, so we can outrule that.

 

Did you check the rear hose (head to matrix) for splits after the accident? That one is very prone to splitting due to the heat of the manifold perishing it.

 

Kev

[corradovr6sc 0]

the radiator- many vr6s spring leaks because of the higher temps/pressures, thermostat housing is plastic and can crack due to heat, heater matrix-check for water in the footwell, after-run pump, drain screw on the water transfer pipe?

[Solitaire 0]

Cheers Kev & corradovr6sc,

 

One of the technicians at work has had the car up on the ramp yesterday, and followed kev's notes, the leak is definately from the thermostat housing or plastic pipe ajoining it, the drips are running down the front of the gear box, there appears to be a gasket on the thermostat housing and it may be coming from this join, anyway, he has offered to come with me to VW in the week to get the parts, although he reckons replacing the plastic pipe looks a very tricky job, any ideas on the best way to go about it guys? and i suppose being a corrado that the parts are quite expensive (had to pay £55 the other day for the headlight switch!)

 

Need to get it fixed soon, as planning to sell it to buy a late blackberry car with a little lower miles, then again, i need to find the blackberry one first, or sell mine and drive an escort van until another one comes along (not very appealling! - doesnt quite give the same adrenalin rush when ya put ya foot down!)

 

There are also three electrical plugs located close to the thermostat housing, and the plastic around them appears to be broken so the closest plug is loose, does anyone have any idea what these are for?

 

Cheers guys, Caroline

[corradovr6sc 0]

The three electrical plugs are senders (measure coolant temp etc. on the mfa/guages) and are colour coded and are held on by clips and are sealed against the thermostat housing with rubber o-rings.

 

The thermostat housing is attached to the cylinderhead with three quite long hex-bolts and is sealed with a rubber o-ring. If you are changing the thermostat there is another rubber o-ring and a round o-ring for both ends of the plastic pipe. It's possible that the thermostat housing is cracked and may require replacement but it's made of 2 or 3 separate pieces so you don't have to buy the complete housing.

Not too sure on prices. O-rings are a couple of quid, thermostat is about £20, plastic parts probably £20-30 each.

[stu 0]

I had to replace the thermostat housing due to a crack, where it mates with the block. With it being a thermoset plastic, the age and heat cause it to disintegrate.

The whole job was less then £30 with a complete set of new seals. by removing the relevant coolant pipes, the job is fairly straight forward, and can be done in half an hour. :)