Thermostat housing leak / seal

As usual with these things I think there's more than one design / make John. I can't remember but I think it was purchased as a v6 turbo stat - not that it helps much.

I'll see if has the temp rating marked on it. It was in the car working, but I think I swapped to a fresh one just for the sake of it.

Sniffer test on the coolant is a good idea. By all accounts they're quite reliable and should confirm if any exhaust gases have made their way into the mix.

I've been thinking about getting a block test done, if nothing else, to eliminate another variable and put the nagging doubts in my mind to rest. The compression test numbers from clee were pretty reassuring, decent numbers and small variations from cylinder to cylinder but need to eliminate that doubt a little more.

I see kits available to do the test oneself for about £35. They are apparently fairly accurate at sniffing any hydrocarbons in coolant but of course, they have no quantitative measure to them.

I'm pretty confident you don't have any blowby issues and its just finding all the weak points after recomission,dodgy new tank,stat,hoses......Temps are staying down even on track and it drives many miles ...I remember on Darrens we had a cracked liner and that would get about 30 miles before going way into the red and you would see it creep up on the gauge way into the red and past .

I'm pretty confident you don't have any blowby issues and its just finding all the weak points after recomission,dodgy new tank,stat,hoses......Temps are staying down even on track and it drives many miles ...I remember on Darrens we had a cracked liner and that would get about 30 miles before going way into the red and you would see it creep up on the gauge way into the red and past .

Cheers Lee, now I can be paranoid about liners instead of HG....... Just popping out for a 31 mile drive

Think it may have something like 50 miles from dead cold ...here to Stoke-on Trent on the way up to RRoad in Runcorn ...from then on less and less distance before having to stop ....


But then again Bob from Norway got from here to there with no issues before having to pull the heads some days later ..... That one had stood for a while also ......

Darren ..... the stat in your pictures you say, has a jiggle valve, also the lower disc is smaller than the GTA original stat, It looks very much like a 610 stat with the jiggle valve and smaller disc ......... and temperature rating of 86 degrees.
Can you put my mind at rest please.

Sorry John. Motorad Germany is the only marking on it. From memory it was a v6 turbo / alpine listed part, but that's all I remember.

Sorry John. Motorad Germany is the only marking on it. From memory it was a v6 turbo / alpine listed part, but that's all I remember.

No problem Darren ...... however, a thermostat with the smaller disc than the GTA OE one, is not likely to be able to cut off the larger port, once up to temperature, at the base of the GTA thermostat housing ...... hence the larger disc.
The 610, on the other hand, has a smaller port in its stat housing.

I have a funny feeling John that the one I'm currently running uses the larger disk.

Since the system is drained at the moment, I might well check - just for my own edification!

[Alpineandy]

I'm sure those more knowledgeable will shout if this is a dumb Idea, but I'd be inclined to drill a few holes in the new stat which would at least let some flow before the late opening. 3 or 4 about 4 or 5mm which would slow the warm up a bit, but not too much. As a side effect it would ease the bleeding as well.
Awaiting knowledgeable thoughts in response!

..... but I'd be inclined to drill a few holes in the new stat which would at least let some flow before the late opening. 3 or 4 about 4 or 5mm which would slow the warm up a bit,

Sorry, but I can't see that as being any help at all.
If a Thermostat is operating as it should, and you still get overheating .... there is another cause. I would not try to overcome the problem, but, instead, fix it.
These Alps were designed to operate at the given temperature, and do so, as long as everything else is working correctly.
The only reason I recommend drilling a small hole in the stat is to stop an air pocket from forming under the stat when refilling the cooling system, as the bleed nipple on the stat housing is in the wrong place, ie:- above the closed stat. .

I'm sure those more knowledgeable will shout if this is a dumb Idea, but I'd be inclined to drill a few holes in the new stat which would at least let some flow before the late opening. 3 or 4 about 4 or 5mm which would slow the warm up a bit, but not too much. As a side effect it would ease the bleeding as well.
Awaiting knowledgeable thoughts in response!

I can see your thinking here on the basis that my current thermostat might be a bit slow, I can seal the thermostat housing, get the temps up a bit higher, retain the secondary function of the other disc, easier bleed for sure and not risk further unnecessary bursts if thermostat is at fault. Question is, when is a jiggle no longer a jiggle?? 2mm, 4mm, ??

I could just get another one too I suppose.

I'm sure those more knowledgeable will shout if this is a dumb Idea, but I'd be inclined to drill a few holes in the new stat which would at least let some flow before the late opening. 3 or 4 about 4 or 5mm which would slow the warm up a bit, but not too much. As a side effect it would ease the bleeding as well.
Awaiting knowledgeable thoughts in response!

I can see your thinking here on the basis that my current thermostat might be a bit slow, I can seal the thermostat housing, get the temps up a bit higher, retain the secondary function of the other disc, easier bleed for sure and not risk further unnecessary bursts if thermostat is at fault. Question is, when is a jiggle no longer a jiggle?? 2mm, 4mm, ??

I could just get another one too I suppose.

You want to avoid fudging this. A small hole in place of the jiggle is fine, but that's just there to aid bleeding. The stat is there to get the engine up to temp and hold it steady - you won't achieve that with extra holes and you'll run the risk that you never get onto the proper ECU map. Potentially you'll always be on the warm up cycle and you'll be running with extra enrichment etc etc, so all in all sorry but not a good idea. By the same logic that's why you need the stat in the first place, and whilst it can be a useful test to take it out (to check for other issues in the coolant circuit) it's really not an effective fix beyond that.

I'm sure those more knowledgeable will shout if this is a dumb Idea, but I'd be inclined to drill a few holes in the new stat which would at least let some flow before the late opening. 3 or 4 about 4 or 5mm which would slow the warm up a bit, but not too much. As a side effect it would ease the bleeding as well.
Awaiting knowledgeable thoughts in response!

I can see your thinking here on the basis that my current thermostat might be a bit slow, I can seal the thermostat housing, get the temps up a bit higher, retain the secondary function of the other disc, easier bleed for sure and not risk further unnecessary bursts if thermostat is at fault. Question is, when is a jiggle no longer a jiggle?? 2mm, 4mm, ??

I could just get another one too I suppose.

You want to avoid fudging this. A small hole in place of the jiggle is fine, but that's just there to aid bleeding. The stat is there to get the engine up to temp and hold it steady - you won't achieve that with extra holes and you'll run the risk that you never get onto the proper ECU map. Potentially you'll always be on the warm up cycle and you'll be running with extra enrichment etc etc, so all in all sorry but not a good idea. By the same logic that's why you need the stat in the first place, and whilst it can be a useful test to take it out (to check for other issues in the coolant circuit) it's really not an effective fix beyond that.

Well, in the interests of science, decided to drill 2 x 3 mm holes. I can't see this keeping the temps down under normal operating given their relatively small area compared to the area of a fully open thermostat. It will certainly perform the jiggle function. Took the opportunity to make sure the car's dash temp gauge was accurate whilst sorting ecu earth issue the other day. Reassuringly, dash temp gauge agrees closely with a thermometer in expansion tank. Done a few test miles today without thermostat and difficult on road in these ambient temps to get above the 70 C mark. Will refit thermostat this week and report back. Was also able to watch coolant level rise as temperature increases. It's more that I expected but there's a lot of coolant to expand so probably normal . What is the correct fill level when cold, is there a level mark on expansion tank? Perhaps I've been overfilling which could have contributed to hose bursts.

I also noticed today that I don't have warm air from the centre vents in the car. Two outside vents get toasty but nothing but cool air from centre dash vents. Is this normal or do I have an issue in the matrix?

Original expansion tanks have a stub in the middle with a notch cut into it. Max level should be at the top of the stub, min at the notch.

Cool air from the middle vents is the norm, check the manual for the coloured air diagram and you'll see it all described.

Let us know how you get on with the stat back in place.

Original expansion tanks have a stub in the middle with a notch cut into it. Max level should be at the top of the stub, min at the notch.

Cool air from the middle vents is the norm, check the manual for the coloured air diagram and you'll see it all described.

Let us know how you get on with the stat back in place.

That's a relief re the vents. Cheers

I had been filling to higher than the stub originally. Now at the correct level.