Coolant temp problems - Confirmed HGF

[steve_weegie]

ps... As the general consensus is that its still air, unless anyone tells me this is a bad idea, the plan for tomorrow is:

Fill tank to brim
Get the front left really high using a hill / jack combo
Warm the car up for a good 10 mins
Give it monster beans & let out an entire tankfull through the front bleed screw.

Cheers,

Steve

[robin]

If you fill the tank to max line (instead of normal min=cold line), put on the cap, then run the engine and monitor the indicated coolant temperature. Be sure to know where the coolant level was before you started the engine.

What you should see is this:

Initially coolant temp rises steadily to around mid-80s. During this time both sides of the radiator should be at ambient (= very cold!) temperature.

The coolant level should rise in the tank.

When you reach the mid-80's it will level out and maybe even fall off a bit. It should sit at this temperature for maybe 5 minutes or so. During this time, heat should spread across the radiator, and eventually the engine bay pipe with the bleed screw in it will get warm.

The coolant level should rise further in the tank.

Eventually, all the coolant will be hot and the engine temp will start rising (note: on S1's, air cooling alone is often enough to prevent you getting beyond this stage, but S2's with less rad circulation at idle typically do get hotter).

Now the temp should rise to somewhere around the mid-90s at which point the fan will come on and eventually the temperature will drop back.

The coolant level should stabalise at this point and remain pretty much unchanged no matter how much longer you run it.

Switch off after one or two fan cycles.

Things to note from this experiment:

(1) Did the fan manage to bring down the coolant temperature?
(2) Did the level of coolant in the tank go up or down?

If the fan did manage to bring down the coolant temperature then you have at least some circulation through the radiator.

If the coolant level went down at any point then you have air in the system (the air compresses under the pressure created by increasing coolant volume during engine heat up). If the coolant level only ever went up, you most likely do not have any air in the system.

Cheers,
Robin

[fd]

eh, nose down will not help at all . . . pax up, nose up s the only state that will work.

Fd

[steve_weegie]

Robin, thanks for the info - i'll try that tomorrow morning. I know from yesterday that when the fan cuts in, the temp drops from 100 down to 95, so there is at least some flow thru the rad. Might whack the ezbleed on the header tank and see if the coolant level drops too.

FD, Nose down was only when i was bleeding it from the engine end. I had the notion that somehow an airlock had got into the return pipe and wasnt shifting so tried it from the other end. Unlikley i know but i was running out of ideas by that time!

Cheers gents,


Steve

[steve_weegie]

Ok, its definatly air. Put the ez bleed on the header tank at 15psi and watched the level drop by about 2". I have bled 12, yes twelve, litres of coolant through the system today and there is still air getting into the radiator.

After a few ezbleeds while cold, refilling the system in between and with the left side jacked up high i take the pressure off and squeeze the outlet pipe. Sometimes i hear air near the output side of the rad, sometimes i hear it at the inlet side. Had a lot of air out while bleeding - steady streem of cooland followed by spurts of coolant / air mix.

Go for a run to get it warm, let it cool down with the pax side jacked up and repeat the process.

I cannot believe this is just an airlock anymore - there's got to be air getting in somehow. What's confusing is that the system seems to hold pressure at 15psi - no level drop on the tank what so ever...

Only good thing was that halfords had a 3 for 2 deal on their coolant!

Cheers,

Steve

[steve_weegie]

Well, st andrews and back today and the car was being a royal pig in the temperature stakes. Going to live with it for a couple of weeks until i can drain the coolant, fit a new heater matrix (needed anyway), fit a remote stat, check all hoses and then refill, hopefully with no air....

If it fixes the problem then i'll be happy. If it blows up in the mean time, i wont.

Does anyone know how easy it is to modify the land rover kit, or is the money better spent on the eliseparts kit?

Cheers,

Steve

[woody]

http://wiki.seloc.org/a/Fit_a_PRRT

Seems fairly comprehensive.

[fd]

I believe that hypothetically and perhaps even practically the PRRT kit is better than the OEM stat (certainly in a freelander) . . . but . . . many, many cars are running with the OEM stat with no problems whatsoever . . . personally I've done 90K miles over 2 engines (first one started drinking oil, but no other issues, dead pistons) many of those miles at full fun mode and with a modded engine . . . and I see no need to d1ck about with the plumbing . . .

You're about to commit the cardinal sin of debug . . .

Changing more than one thing when you don't know what is wrong . . .

As for air ingress . . . you may well find that the system pressure seems stable under pressure but absolutely fills with air under negative pressure (cooling), because of the somewhat different viscosities of water and air . . .

If you have hydrocarbon checked it and it's a no result then the answer is simple . . . air/coolant leak . . .

Now . . . remind me . . . did you ever fit a brand new header tank cap ?

Personally I see no need for the huge revs and bleed technique . . . you should not need more than slight positive pressure in the system . . . which I am wondering if you are getting . . . does it ever pressurise ? . . . if not then the header tank cap is dead (even if you think it isn't) and that is the root of all evil . . . with no pressure the system simply does not work . . .

It would be interesting to have a play and see what a second set of eyes can see . . .

I'm in Abernethy, so not a million miles from St Andrews on the way home . . .

Fd

[steve_weegie]

Ta

Another bit of seloc i havnt discovered...

[steve_weegie]

Hi Fd,

Yup, i was going into old school gwbasic mode and the redo from start approach! Sin I know, but im at my wits end with the thing at the moment. The temp adjuster on the matrix is goosed so needs changed sometime, and while i was dropping the coolant i reconed it would be a good time to swap it out and fit a PRT.

I'd be really grateful if you'd like to have a look at it sometime - i'm in st andrews all week so just let me know when would be convenient and i'll pop across.

I nicked mac's header cap of his cat and still have the same results. The system definatly pressurises as when you remove the cap from the hot header tank, you hear a lot of pressure release. Also, front return pipe is pressurised.

If i leave it nose up on a hill to cool, i'll get air out the front bleed screw with pressure on the header tank. 9 times out of 10, i'll also hear air in the rad inlet hose after i'm done and give the outlet hose a squeeze. I had a peek at the foam on the rad, especially round the inlet hose and it seems dry and fine.

All in all, its confusing the hell out of me!

Cheers,

Steve

[fd]

not at home tomorrow, perhaps not weds (although I can be if that helps - easily cancelable) thurs also is possible, I'm off to London early on Friday tho so not too late on Thurs . . . let me know your thoughts/plans, can be in abernethy for 1800 usually . . . busy week at work tho so best make a positive plan . . .

Fd

[steve_weegie]

I'm pretty flexible about when i can pop across, so just name a date & time and i'll be there!

Cheers,

Steve

[tut]

Steve

Do you have AA parts and labour? If not maybe worth taking it out.

tut

[mac]

There is positive presure in the system - you can feel it when you release the cap, there's actually a fair bit as it was forcing the cap up against the threads when I was releasing it to check for HC's


Mac

[fd]

And you're 100% sure that the HC test is negative ?

This does have all the hallmarks of HGF pressurisation, but if the sniffer says no . . . then no is the answer . . .

Has anybody had the spark plugs out to check condition ?

Fd