Cooling Problems (8V)

[chown]

Hi all,

I've read various postings about all sorts of cooling issues on here, and i wondered if anyone might be able to help with mine.....

This has gotten quite complicated so forgive the confusion and possible red herrings :-s

I first noticed a grumbling water pump so hence replaced with a recon unit. All was well. I then noticed i was leaking coolant... Turns out i'd aggrevated the poor condition of the hard steel coolant pipe which runs up the right hand side of the block.... Replaced and all was well.

I then replaced my front engine mount (engine rocking) and must have accidentally dinked the fan cowl on refitting. Of course i didn't notice this until i was stuck in traffic with the temp gauge at 3/4! Running the heater full blast controlled the temperature at first until i was stuck on the M40 when my heater would occasionally blow cold. (I'd read about air locks and removed a heater pipe on coolant refilling and ran the engine at first without its header tank cap on). Anyway I got home with heater mostly blowing hot to investigate further.

I replaced the fan motor fuse and again all was fine. The car has run like this for a couple of months without fault until yesterday i was again stuck in traffic and the temperature lifting toward 3/4. Heater on full blast and the temperature plummited so got home to investigate. The cooling fan cut in and all seemed ok. I was thinking that maybe the thermostat had got lazy and opened late. It was at this time i noticed the coolant was low so I topped it up. Strangely now the coolant level is high :-S

With a hawk eye on the temp gauge i notice the needle isn't as rock steady (at half way) like it used to be, it fluctautes slightly as i guess the thermostat is lazy (I stupidly didn't replace the thermostat while the w/pump was off).

I keep wondering did the car over heat slightly without me noticing (while the fan motor was inoperable) and the head gasket is starting to go? There is no oil in the water, no water in the oil, it starts straight away every day, and the performance hasn't dropped. I will check the plugs at the weekend, but don't you agree this all these cooling problems look a bit suspicous, or is it extreme bad luck?

The car is totally original, with a huge full history and only 84k on the clock.

Any help would be greatly appreciated!

Thanks.

[Organisys]

Sounds like the thermostat, or the fan switch is cutting in too late.
Run the car from cold, does the bottom rad hose get warm after a while?

[Mr Blue]

take off the pipes that go to the heater matrix.

using a hose pipe. flush the matrix. put pipes back on


use a nice mix of anti freeze and bleed the system properly (cap off). It will take a while

[chown]

Thanks for your help guys.

If ran from cold the bottom hose gets hot but much later then before, the temp gauge needle goes past the vertical and then stays steady on the white line, and then 20 seconds later the fan cuts in. I agree this sounds like a lazy thermostat, but the problem is I'm losing water! I've had everything apart so i guess i could have a hoseclip loose.

What might the syptoms if the head gasket was just about to start to go? Lets say if there was a slight path between cylinder and water jacket rather than between oil and water.

Thanks again

[rubjonny]

the fan on an 8v should be a 2 speed jobber, make sure the slow speed isn't fried or the fan thermoswitch isn't knackered!

If the HG had blown between a cylinder & water channel, the coolant would be overpressurised and filthy!

[jase555]

if you take your car to your friendly local garage and ask them to test the coolant for emitions that should confirm that you have or haven't  got head gasket problem.

[chown]

Thanks all,

I've found a leak on the temp sensor boss, replaced seal but head is pitted by corrosion and still weeps at mo.

I'm still losing lots of water (poss half a pint a day - 30miles worth) and can't believe a tiny weep would cause this. Anyway I'll hopefully cure leak at weekend and take things from there.

By the way, I replaced the thermostat too, but the temperature still fluctuates slightly where as before the needle was rock solid.

Cheers