RR Classic 3.9, It's a headgasket, isn't it?

[pacoryan]

Evening all, my project was recently returned to me with intact flooring so I set about the other jobs and actually driving it. This didn't last long until it overheated, failed thermostat was the first port of call and lo, it was indeed kaput. much fiddling later and I have the new stat fitted, (two gaskets later) and yes I tested the new stat before fitting having learned from that mistake before.

Thing is the system is over-pressurising. Temperature on the guage is fine, but upon return it's p'ing out through the filler cap. I followed the Rave instructions for refilling as well.

Now comes the confession - when the stat failed it got hot, and I mean really hot - I was stuck with the kids in the car and frankly getting to safety was more important than the survival of my heap. So have I cooked a gasket or is there anything else I should try? Coolant clear of oil and oil clear of coolant, no steam in the exhaust.

I am now out of time due to a family health situation and moving later in the summer, so if it is HGF it will be done by someone else and soon, but is it worth me trying anything else?

Oh and it is on LPG - or it would be if it worked.... so I'm aware HGF is even more likely!!!

Wine poured - responses awaited!! (be gentle)

[paintman]

Stat fitted with bleed hole at 12 o'clock position? Sure the stat does have a bleed hole?
Get the coolant checked for the presence of exhaust gases. This is a 'how to':
http://www.youtube.com/watch?v=1_SIwHMLmkM

[Simes110]

I once had a 3.9 D1 in Australia that did exactly what yours is doing. And that was after the supplying garage replaced the heads....

Had it checked and there was coolant in the oil.

The one thing the garage didn't do, but SHOULD have done, was flush out or replace the radiator as these are known for silting up. Mine had silted up (bloody muppets and stupid me for being so incredibly niave), and that overpressurised the system and blew the heads.

So check your radiator very thoroughly.

The one thing that CAN cure your malaise, and it's cheap, is the header tank cap can fail. This also results in loss of coolant from the header tank, as you've described. So check that first.

[pacoryan]

Thanks very much, header tank cap is a good idea, the radiator looks quite recent and when I blew through the top hose plenty of coolant came out of the bottom house without much effort. I haven't taken the rad out yet though.

Oh yes and my replacement stat didn't have a bleed hole, so when I refitted it (having removed it to test it and replace the damaged gasket) I drilled a small hole in and installed it with the hole at 12 o'clock. I can't get the top coolant filler cap off without destroying it either, but having not emptied that loop I don't think I need to - the heater is blowing hot.

Edited by pacoryan on Thursday 3rd July 12:53

[paintman]

I wonder if you had an air lock & its cleared itself. Managed to do that on mine (3.5EFi) after emptying the system & it overheated on tickover followed by a fairly spectacular gush of water from the pressure cap. No problems since & I hadn't managed to do that before!
The test I showed will give a better idea as to whether its a hg or not.

Edited by paintman on Thursday 3rd July 20:39

[camel_landy]

When the head gasket goes, it's not uncommon for it to go between Cyl 1,2,7 or 8 and the coolant channel right next to it. Instead of coolant coming into the cylinder, gasses enter the cooling system and gives you the symptoms as described.

M

[pacoryan]

Thanks M, that's still my fear. Due to my father being hospitalised I have been limited on time so haven't made much progress. On the w/e I established that there might be a circulation issue though, I ran it to operating temp without the expansion cap on (as per Rave refilling instructions) and the top hose got hot, but the expansion tank didn't, suggesting it isn't circulating well.

The "cheap" option of a replacement expansion cap is not so cheap, £50 in fact because of the level sensor included!! I shall swing by the hallowed specialist and give him back the AMM he lent me and see if he has a known good expansion cap and a coolant testing kit I think!!!