Coolant temp problems - Confirmed HGF

steve_weegie · Post by **steve_weegie** » Mon Jan 21, 2008 9:01 pm

Hi guys, just back from st andrews to glasgow and the car was running fine 99% of the time, with the usual slow down / temp rise nonsense.

Off to have a cuppa then as i've got the car on a big hill with the nose in the air, i'll see if i can get any air out the radiator.

Keep you posted & cheers for all the advice so far!

Steve

steve_weegie · Post by **steve_weegie** » Mon Jan 21, 2008 10:24 pm

Ok, there's an alarming ammount of air in the system.... I noticed the bleed screw had a faint trickle of coolant round it, and it was screwed in tight when i started.

Return hose from the rad feels empty, rad bleed screw open and no fluid emerges at 100 deg temp. Had to put the pressure cap on and rev it slightly to get any fluid to come out.

Off to try again, this time in a non-residential area.... Fingers crossed i'll be able to shift the block with some revs and keep bleeding it.

Worrying thing is i missed halfords tonight so will be topping up again with plain water....

Cheers,

Steve

fd · Post by fd » Mon Jan 21, 2008 10:38 pm

Dude, if you're bleeding it with the pressure cap OFF then you are making it worse not better . . .

bleed procedure that I use . . . never failed yet . . .

let system cool, remove then immediately replace pressure cap (zeros the system pressure to atmospheric), start engine and allow to warm right up to fan temp . . . this pressurises the system . . . put on your very thin but totally hear resistant gloves . . . drive car left hand front wheel only up onto a kerb . . . arrange a torch so you can see the front pipe bleed screw . . . undo it a little . . . you should get gas then bubbly coolant out . . . if it stops or goes to pure coolant then screw back in . . . if you got to clear coolant then it's done, if not then you ran out of pressure . . . take it for a thrash and repeat . . .

Repeat 2 or 3 times over the next few days . . . you will have a perfectly bled system

You could do all this with a gunson brake bleeder and a very flat tyre as a pressure supply too . . . this is what I use these days as it avoids the burned hands bit . . . threaded cap is the same on the brake res and the coolant tank . . .

Also it'snot unknown for the bleed screws themselves to leak, usually not properly bonded into the pipe . . . IIRC Iain Watt had this very problem . . . on an S2 . . .

Fd

Rich H · Post by **Rich H** » Mon Jan 21, 2008 10:40 pm

sh*t not good

water is ok as long as it does not get too cold up there.

Victor Meldrew · Post by **Victor Meldrew** » Mon Jan 21, 2008 10:54 pm

On the assumption that it is the heater matrix, is there any reason I cant blank it off?

I was thinking about fitting a couple of valves on the supply and return lines, that way I can isolate the heater matrix and prove or disprove either way if it is the matrix before I go down the HGF route. Pretty convinced that it is the heater now.

I have read that some track bandits fit a valve to put all the coolant through the radiator when on track to help with the cooling...

Rich H · Post by **Rich H** » Mon Jan 21, 2008 11:01 pm

remember that the matrix is permanently in the cooling loop so it will raise water temps quicker but not the oil temps.

Victor Meldrew · Post by **Victor Meldrew** » Mon Jan 21, 2008 11:03 pm

RICHARDHUMBLE wrote:remember that the matrix is permanently in the cooling loop so it will raise water temps quicker but not the oil temps.

Youve lost me there?

Rich H · Post by **Rich H** » Mon Jan 21, 2008 11:42 pm

The heater matrix acts like a small rad all the time, cut it out and the coolant will apparently heat up quicker as the volume of water avaiable to cool the engine is smaller but the oil will take pretty much the same time. Basically ignore the coolant temp and warm up like you normally do.

Just thinking out loud really. Sorry, I'll shut up now...

Victor Meldrew · Post by **Victor Meldrew** » Tue Jan 22, 2008 12:35 am

RICHARDHUMBLE wrote:The heater matrix acts like a small rad all the time, cut it out and the coolant will apparently heat up quicker as the volume of water avaiable to cool the engine is smaller but the oil will take pretty much the same time. Basically ignore the coolant temp and warm up like you normally do.

Just thinking out loud really. Sorry, I'll shut up now...

Ah... with you now. Makes no differance though as I normally rag the sh*t out of it from the first turn of the key

steve_weegie · Post by **steve_weegie** » Tue Jan 22, 2008 12:47 am

Right, just back after 1.5 litres of water and some burnt hands. Cant do any more tonight as I dont feel comfortable dropping the antifreeze mix below what it is at the moment.

Ok, heres what i did....

Warmed engine up and took for a blast. Temperature was about 95 - inlet side of radiator very hot, outlet side stone cold. Parked up on a big hill with the front left on the kerb. Pressure cap on this time

With the engine running, I took the bleed screw out and tons of air escapes. Coolant emerges - burn hands, swear lots but get screw back in. Put on 2 pairs latex gloves....
top up tank & go for a blast.

Repeated this a couple of times, noteing the cooland level and if it dropped when i rev the engine. It did, and unfortunatly still does. Temperature doesnt seem any better either.

I'll have another go tomorrow night after i get some coolant, but the question of how all the air (and it's a lot) got into the system still remains... I'm off to Mac's on wednesday night to do the sniffer test. Spare pants will be taken...

fd wrote:put on your very thin but totally heat resistant gloves . . .

I need a set of those! Skin does conduct heat rather too well! Do they come in pack saying "if carling did latex....."

RICHARDHUMBLE wrote:sh*t not good

water is ok as long as it does not get too cold up there.

Fingers crossed! Its supposed to be -3 but im in the city center so hopefull it wont drop too much.....

John, fingers crossed it IS your heater matrix... Do you still need the gas sniffer?? I'm seeing Mac on wednesday if it helps?

Thanks for all the help guys - will keep you posted,

Steve

fd · Post by fd » Tue Jan 22, 2008 12:51 am

All may not be lost . . .

It takes a few iterations to get all the gas out . . . (that you've just put in !) . . .

Don't panic !

Fd

steve_weegie · Post by **steve_weegie** » Tue Jan 22, 2008 12:57 am

fd wrote:All may not be lost . . .

It takes a few iterations to get all the gas out . . . (that you've just put in !) . . .

Don't panic !

Fd

Aye, spot the coolant bleeding newbie

Should i be bleeding it with the engine on? My thinking was that i should be using the water pump pressure rather than the system pressure to do this? It is possible i may be wrong though!

Cheers,

Steve

mac · Post by **mac** » Tue Jan 22, 2008 8:19 am

Steve,

I'm on nights tonight (hence coming over tomorrow) but that does mean I should have time to find the presuriser thingy.

Failing that it's the patented Macbleed system - if I remember to pick up some rubber gloves first

Mac

robin · Post by **robin** » Tue Jan 22, 2008 9:22 am

John,

It's not a good idea to blank off the matrix pipe completely as it forms half of the bypass circuit for the coolant system.

However, if you just want to isolate the matrix to see if it's the source of your coolant leak you can bypass it with a bit of pipe - if you can find steel or alloy that would be better than using copper, but running with a bit of copper central heating pipe for a couple of days isn't really going to matter.

Steve: when I've refilled the cooling system I usually just bleed it out from the engine bay to start with; Fd's method is good for getting remaining gas out of the system, but if you have a lot of air in there, you may have better results starting out this way before you bleed the rad:

Jack up the rear of the car/drive on ramps/drive on kerb so that pax side rear is above other three (it doesn't have to be a huge difference). With engine cold (or at least not hot) and stopped, remove engine bay bleed screw in metal rad return pipe (it's below and forward from the throttle body).

Now fill the tank to the brim, but try and do it without swirling the coolant in the tank (which will pull more gas in with it). Eventually you will get to the point where coolant fountains out of the bleed screw. Put the screw back in. Top tank right up to the brim and replace expansion tank cap. Start the engine and while it's still cold, rev to 2,000 RPM or so (you can use the tip of a tie wrap stuck in between the throttle stop screw and the throttle to keep a steady engine speed).

Open and close the bleed screw repeatedly and you should get air coming out and eventually just coolant. While the engine is still <90 or so you can remove cap, brim tank, replace cap - just make sure you always keep the coolant above the max line. Once the engine gets to the point where the stat opens you need to stop, allow to cool, refill tank, repeat.

If you really want to get evil with the air in the rad then go straight to 4,000 RPM with the tank cap on and the tank brimmed - this puts maximum pressure on the air in the rad, compresses it and hopefully forces it into the rad return pipe, from where you can bleed it out of the return pipe in the engine bay - beware that coolant pressure will be quite high in this case and so the spray from the bleed screw will be significant!

Cheers,
Robin

Victor Meldrew · Post by **Victor Meldrew** » Tue Jan 22, 2008 9:48 am

robin wrote:John,

It's not a good idea to blank off the matrix pipe completely as it forms half of the bypass circuit for the coolant system.

However, if you just want to isolate the matrix to see if it's the source of your coolant leak you can bypass it with a bit of pipe - if you can find steel or alloy that would be better than using copper, but running with a bit of copper central heating pipe for a couple of days isn't really going to matter.

Cheers,
Robin

was thinking this myself, and a small bit of scrap pipe is cheaper than buying two valves... thats the Fifer in me kicking in....