Head gasket replacement

[Dirty Rooster]

Originally Posted by Volvoluke

I am going to be doing the head gasket on my 940 2.3 ... ... Any input or tips would be appreciated

I also want to know why as this affects everything else.

I've done it twice,
once sending the empty head off for skimming & new valve seals etc, then replacing the valves (evil little split valve cap thingies!) and all that fiddly bucket-shim stuff,

next time was head off, fix problem, head back on ASAP.

Two very different situations.

[Volvoluke]

To answer the question why change the head gasket. I will try to explain the symptoms. My car for the past 3 years out of the 5 I have owned it for has had a external head gasket leak under the exhaust manifold. However the main problem seems to be with the water pump being over pressurised to the point that I now empty my header tank within 10miles no to mention I'm not driving it. The car has also developed a recent rough idile on start up when cold. I have considered changing the water pump again before attempting a head gasket change however I do feel I could be wasting my time as from my research it does seem to be the head gasket, obviously the pump has been changed before but only provided temporary relief. Although I am not convinced of the quality of the pump.
Let me give a little more information on the car. It has 220k and has previously had the head gasket replaced by volvo at 110k.
If anyone is interested I will get some pictures of the external leak which to be honest hasn't worsened over the years. But the coolant consumption has got out of hand and I'm convinced it isn't just down to the pump. However if anyone thinks it is then please let me know

[Dippydog]

The leak below the manifold is it a coolant leak or just blowing from there?If just blowing could it be the manifold/manifold gasket that's gone in that area? A compression test and/or a "sniff" test might be worthwhile before lifting the head?

[KBB]

I would recommend a CO sniff test of the header tank and a cylinder leak down test prior to concluding you have a Head Gasket issue. Those results could lead to a completely different diagnostic path!

[Stephen Edwin]

Lots of good advice there from all of you in my opinion. Basically, get more diagnostic information before deciding what to do.

After all, a step in the wrong direction leaves one further away from one's destination.

*****

KBB. What is a cylinder leak down test please? I get the idea I think but how is that done please?

[Dirty Rooster]

Originally Posted by Volvoluke

...l head gasket leak under the exhaust manifold. However the main problem seems to be with the water pump being over pressurised to the point that I now empty my header tank within 10miles no to mention I'm not driving it. The car has also developed a recent rough idile on start up when cold...

After a broken hose and overheating my headgasket was also causing overpressure in the water system ;
the garage simply checked for gases in the water and bingo! Diagnosed.
Another tell-tale was very hard waterpipes to/from the radiator when engine running.
(Long story short swapped the whole engine)

In your case Luke if the engine hasn't actually overheated all your head gubbins might be fine so keeping costs down on your headgasket job.

[arctan]

I'm gearing up to do my (1997) b230fk head gasket.
It might or might not be the same part for yours?
Elring may or may not be OEM?
I keep seeing this Elring part number (701.055) in a few places:

https://www.mister-auto.co.uk/cylind...haracteristics

And, more cheaply:
https://www.ebay.co.uk/itm/New-Genui...-/401456434830

I'm thinking PCV box clean or replace (seal needed), fit the metal heater valve I've got lying around, do the bosch crankshaft sensor. My car is LPG'd and I've had aggro from the three above (on previous 940 lpg), in part because lpg may run a tad hotter than petrol.

YMMV!

[Laird Scooby]

Originally Posted by arctan

I'm gearing up to do my (1997) b230fk head gasket.
It might or might not be the same part for yours?
Elring may or may not be OEM?
I keep seeing this Elring part number (701.055) in a few places:

https://www.mister-auto.co.uk/cylind...haracteristics

And, more cheaply:
https://www.ebay.co.uk/itm/New-Genui...-/401456434830

I'm thinking PCV box clean or replace (seal needed), fit the metal heater valve I've got lying around, do the bosch crankshaft sensor. My car is LPG'd and I've had aggro from the three above (on previous 940 lpg), in part because lpg may run a tad hotter than petrol.

YMMV!

What spark plugs and plug gap are you running?