v8james · Oct 20, 2015

A few months ago the engine started using water since it had done 140000 miles decided to take head off and replace gasket and rejuvenate head. Head was pressure tested, all ok, and was found to be straight but a light skim was done to take off gasket marks. All went back together fine (after taking the rest of the engine out to change the clutch) and was running great.
Last week my wife said the heater was only blowing cold, I checked the coolant and there was none in the expansion tank and it took 4ltrs!! to refill. I eventually found the hose the goes through the bulkhead to the heater was leaking. I fitted an new clip and all was good until yesterday when I got out and heard a hissing from under the bonnet. The expansion tank cap was hissing and the top hose from the engine was solid but engine temp was ok and heater was blowing hot air.
I assume head has warped or gasket has gone due to low water, is there any way to test this without removing the head (again)?

johnlad · Oct 20, 2015

Fill to correct level and bleed properly then take it down the motorway for about 20 miles, if it boils over then, chances are it's the head as they don't like being run on low coolant

sierrafery · Oct 20, 2015

replace the tank's cap first with new one and bleed the system well, the tank cap MUST be well tightened to seal 100% and in good working order to keep 1.4 bar in the system to raise the water's boiling point to 123*C, if it's not tightened well, it's orings are leaking or it's pressure valve is not working ok the system will be at ambient pressure and the coolant starts to emit microbubbles between 90-100*C which will create overpressure... maybe you are lucky to be only that

v8james · Oct 20, 2015

sierrafery said:
replace the tank's cap first with new one and bleed the system well, the tank cap MUST be well tightened to seal 100% and in good working order to keep 1.4 bar in the system to raise the water's boiling point to 123*C, if it's not tightened well, it's orings are leaking or it's pressure valve is not working ok the system will be at ambient pressure and the coolant starts to emit microbubbles between 90-100*C which will create overpressure... maybe you are lucky to be only that

I replaced the cap when I did the head gasket but will check it is tight. I slackened off the bleed screw last night when the hose was hard and lots of froth came out so waited for engine to cool and more came out before water.

West Slope Rover · Oct 20, 2015

Perhaps a kind reminder to the wife about keeping an eye on the temp gauge is in order.

v8james · Oct 20, 2015

West Slope Rover said:
Perhaps a kind reminder to the wife about keeping an eye on the temp gauge is in order.

Unsurprisingly that was the first thing I said to her, but when I started the engine the gauge what where it should be. But I think gauge out goes into the rad when temp is really high.

sierrafery · Oct 20, 2015

when the gauge leaves the middle it's already late cos it goes up only at 120*C, on a D2 a supplimentary temp display gauge is compulsory

v8james · Oct 20, 2015

sierrafery said:
when the gauge leaves the middle it's already late cos it goes up only at 120*C, on a D2 a supplimentary temp display gauge is compulsory

I will take it for a run tonight with Hawkeye plugged in and see what the correct temp is.

sierrafery · Oct 20, 2015

v8james said:
I will take it for a run tonight with Hawkeye plugged in and see what the correct temp is.

what you see with tester is not the correct temp, it's what the temp sender reads and that's a rudimentary NTC sensor which can be erratic especially if it's very old... though it's more than just watching the gauge which goes to the middle at 70 and rises above at 120*C

sierrafery · Oct 20, 2015

btw, try to stop the viscous fan with a rolled newspaper when the radiator is HOT, and if you can that could be a complementary issue

v8james · Oct 20, 2015

sierrafery said:
btw, try to stop the viscous fan with a rolled newspaper when the radiator is HOT, and if you can that could be a complementary issue

Ok will do, will let you know tomorrow. Thanks for the advice.

v8james · Oct 22, 2015

So after I went for a run to get engine up to temp top hose was solid. I let it cool a bit and opened the bleed valve coolant was a bit frothy!!
Froth turned into water eventually after topping up expansion tank, ran the engine, more froth then coolant. Did this until no more froth came out.
Any idea what this could be?

johnlad · Oct 22, 2015

What ever it is, it don't look right

v8james · Oct 25, 2015

Looks like head gasket is away again as top hose is solid and rad cap is hissing.
Before I take off the head is there a way of doing a leak down test on the individual cylinders?

jamesmartin · Oct 25, 2015

yes but would it help, gasket will show signs of any gasses passing over or under it

discool · Oct 25, 2015

As your calling your self V8james it may be the other head.

v8james · Oct 25, 2015

First Discovery I had was as V8, only problem I had with that was it used fuel as if there was a hole in the tank

v8james · Oct 25, 2015

jamesmartin said:
yes but would it help, gasket will show signs of any gasses passing over or under it

Just wanted to see what cylinder was leaking as could be a cracked head/block and if the gasket was ok when head is removed it would narrow down the search of the problem.
I have a leak down tested for petrol engines what do I need to attach it to the diesel head?

jamesmartin · Oct 25, 2015

piston or ports will be washed if theres a leak
glow plug hole adapters are used but you cant do no 5 on a td5

shaun69 · Oct 26, 2015

What about a sniff test????? Also hows the thermostat??????

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