Overheating

jt_armstrong · Nov 30, 2010

I think my heater matrix has split. I swapped out the 'O' rings a few weeks ago but it continues to leak coolant into the drivers footwell. I have been ruuning the cooling system with water only for the last few months so I could get all the leaks fixed but with the bad weather I decided to bypass the matrix, drain the system and fill her up with antifreeze.

Problem is that now she keeps overheating. It will idle no problem but as soon as you go out for a run it will boil up before you have done a mile. It cools down to normal within a couple of minutes and you can then progress for the next mile.

I assume the problem is air trapped somewhere in the system - does anyone have any good tips for bleeding these things?

ROBV8 · Nov 30, 2010

I would plumb the matrix back in a tip a k-seal in the system to stop the leak mate?

jt_armstrong · Dec 1, 2010

ROBV8 said:
I would plumb the matrix back in a tip a k-seal in the system to stop the leak mate?

I have never used it before but it has some good reviews on the internet. Do you have any experience with it?

jorjio_k · Dec 1, 2010

if ur heater is cracked replace it and avoie having headaches w k seal.k seal and anti freeze won't work together.

fett · Dec 1, 2010

workin ok on mine

jorjio_k · Dec 1, 2010

lucky u lets c for how long lol

ROBV8 · Dec 1, 2010

Sorry for delay. I've used k-seal dozens of times on various different cars and never had any back yet! Bloke I work with had head gasket gone on his focus and it was ****ing water into number 2 cylinder! Put k-seal in and with in 10 minutes picked up onto 4cyls again and still going strong! So I love the stuff personally.

jorjio_k · Dec 1, 2010

ain't k seal the stuff that anti freeze disolve on every coolant flush?well guess if it comes to me i would replace my heater core,mine is bypassed at the moment,i want to fix it,dunno if it is the core or the o rings,guess there is only one way to find out. then maybe i am mistaking k seal with ironite?they rn't the same components?

fett · Dec 1, 2010

18 months so far

jt_armstrong · Dec 1, 2010

Got to be worth a try. Hopefully the roads will be clear enough in the morning for a trip to the local auto parts shop.

jorjio_k · Dec 1, 2010

fett said:
18 months so far

QUICKLY FETT KNOCK ON WOOD NOW NOW NOW she will hear u,believe me she will.

hope it will last 18 years

dunno if i can say don't flush ur coolant,then u will tell "i did it 12 months ago"

lol

fett · Dec 2, 2010

lol , she made it all over today in the snow on mercy missions thank God!

I put two cans in with the coolant when I did a complete change and added another can in after the summer when I lost a bit flushing the matrix, which wasnt blocked in any way shape or form btw. wasted an aternoon there lol

jt_armstrong · Dec 4, 2010

Ok, Tried the K-Seal this morning. Poured the contents into the matrix feeder pipe to ensure it got first shout. Leak in matrix looks to have stopped but still no heat in the cabin. I have bled the system as per RAVE however the bottom radiator hose is not warming up. I assumed that problem was with thermosat and so I removed that for testing. I can confirm that it works fine.

Next thing on my test list is the water pump. Anybody know how I can test this?

fett · Dec 4, 2010

k-seal wins again

odyssey · Dec 4, 2010

If the bottom hose isn't getting hot, then I'd say the most probable cause is a blocked or partially blocked Rad, I had a similar problem - it would idle quite happily for ages and was fine round town, but work it a bit harder and it would overheat. The rad was only about 2 years old so I was sure that wasnt the prob, but eventually realised that it got hot at the top but was cold at the bottom. Tried back flushing it but a garden hose can't give enough flow. Ended up replacing it, problem ended.

You may find that the rad (if blocked) caused the leak ofrom the O rings in the first place.

To check warm the car up, switch off put your hand on the back of the rad at the top and lower down - you have to wriggle your fingers in between the fan blades, and if it's much cooler at the bottom = blocked rad.

A

neville123 · Dec 4, 2010

as we speak my matrix is being replaced by jason good bloke good job and cheap i think? lol

jt_armstrong · Dec 4, 2010

odyssey said:
If the bottom hose isn't getting hot, then I'd say the most probable cause is a blocked or partially blocked Rad, I had a similar problem - it would idle quite happily for ages and was fine round town, but work it a bit harder and it would overheat. The rad was only about 2 years old so I was sure that wasnt the prob, but eventually realised that it got hot at the top but was cold at the bottom. Tried back flushing it but a garden hose can't give enough flow. Ended up replacing it, problem ended.

You may find that the rad (if blocked) caused the leak ofrom the O rings in the first place.

To check warm the car up, switch off put your hand on the back of the rad at the top and lower down - you have to wriggle your fingers in between the fan blades, and if it's much cooler at the bottom = blocked rad.

A

Thanks Odyssey however I only swapped out the radiator for a new one around August. I have been chasing cooling system leaks since March and each time I fix something the next weakest link in the chain gives out. Various hoses, a radiator, o-rings and next I guess will be the matrix. As you can guess I have had to part drain the system many times and have never had any problems bleeding it until this time - hence my thinking that the water pump has failed. No matter what, I would assume that water should always flow in to the matrix and whilst the inlet hose gets real hot the output hose stays cold. Even with air in the matrix I would still expect some hot water to flow through.

fett · Dec 4, 2010

you sure there is not to much pressure in the system with all those cascade leaks?

might be H/G or liners , sorry :doh:

odyssey · Dec 4, 2010

Have you tried reverse flushing the matrix?

The other thought that struck me, (although I'm not 100% sure as I have a classic), doesn't the P38 have a variable valve in the heater matrix hoses somewhere? I had a discussion with Wammers about this and I seem to remember looking at the diagram in Rave. If you're not getting return flow from the matrix either it's blocked (which the K seal won't have helped) or the valve is stuck/inop.

In the classic there is constant flow through the matrix even from cold, when mine got gummed up I swapped the hoses over so it was running 'backwards', getting heat now . . ..

A

fett · Dec 4, 2010

odyssey said:
Have you tried reverse flushing the matrix?

The other thought that struck me, (although I'm not 100% sure as I have a classic), doesn't the P38 have a variable valve in the heater matrix hoses somewhere? I had a discussion with Wammers about this and I seem to remember looking at the diagram in Rave. If you're not getting return flow from the matrix either it's blocked (which the K seal won't have helped) or the valve is stuck/inop.

In the classic there is constant flow through the matrix even from cold, when mine got gummed up I swapped the hoses over so it was running 'backwards', getting heat now . . ..

A

So that works does it? what year classic? mine isnt blocked but doesnt make heat for very long, I had thought of doing this on the off chance somone had swapped them behind the dash accidently before I got it.

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