940 Head Gasket issues?

[Clan]

Originally Posted by Rversteeg

It is quite normal to see white smoke when running on LPG due to the burning process of LPG compared to petrol. Due to the LPG consist, the LPG process relies much more on burning hydrogen to water than carbon to CO2, like petrol. This one of the main reasons LPG is cleaner than petrol. The exhaust gasses simply contain more water. Especially on colder days you will see more white smoke coming from LPG car than petrol/diesel cars.

In general, loss of coolant is more often due to a (hidden) leak than a failing HG. Do you fill to the MAX mark? In that case the remaining system volume often seems to be too small and many 940s will simply cough out coolant via the filler cap until the MIN mark is reached again. Top up when cold just over the MIN mark.
Especially since your coolant level is not stable I would recommend to replace your expansion tank for a tank with a minimum level switch. On my 940 I sacrificed the washer fluid low level indicator wiring for easy installation.

If your LPG system has an evaporator, this could also have an internal coolant leak.


If you have been adding fresh coolant every week, it will be sufficiently recycled by now.

The corrosion which I am talking about will have started many many years ago ..

[deeman940]

Sounds like when mine went, water was running down side so not mixing with oil therefore no 'mayonnaise!'

[kiloran]

I'll add a "me too" to this thread, this is exactly what mine has done. I recall back in the depths of winter there was some steam/evaporation coming front of the head on the drivers side. I'd put it down to condensation and a hot exhaust manifold but suspect it was an early sign of what's become a bigger problem

[Laney760]

So, today I put the car into my garage for head gasket check. It was one of the mechanics who doesn't normally work on my car who said that due to the (small) coolant leak on the side from the head I should have a new head gasket.

Today the garage boss did all the work on my car, he normally does all the work on my car, and he doesn't think I need to renew the head gasket. He found out why I am using so much coolant. Where the pipe goes into the header tank there is a bad leak from either the pipe or the header tank but he didn't want to start taking things apart today in case the pipe was brittle and split and left me carless!

So tomorrow I am going to order up a new header tank and pipe from Volvos. I don't suppose anyone knows the part numbers out of interest?

[Laird Scooby]

Originally Posted by Laney760

So, today I put the car into my garage for head gasket check. It was one of the mechanics who doesn't normally work on my car who said that due to the (small) coolant leak on the side from the head I should have a new head gasket.

Today the garage boss did all the work on my car, he normally does all the work on my car, and he doesn't think I need to renew the head gasket. He found out why I am using so much coolant. Where the pipe goes into the header tank there is a bad leak from either the pipe or the header tank but he didn't want to start taking things apart today in case the pipe was brittle and split and left me carless!

So tomorrow I am going to order up a new header tank and pipe from Volvos. I don't suppose anyone knows the part numbers out of interest?

https://www.partsforvolvosonline.com...oducts_id=5755

That's the expansion tank Ellie, aftermarket but the OE numbers are listed below it. They used to sell the OE tanks as well but as they no longer do i'd make a guess they are NLA from Volvo but could be wrong.

As for the hose, there are two different ones available :

https://www.skandix.de/en/spare-part...-tank/1062295/

https://www.skandix.de/en/spare-part...-tank/1021196/

Both seem to fit strangely!

PS - just checked, the reason both seem to fit is one is genuine and the other is aftermarket, Volvo part number is 9155496 and just happens to fit my 760 too which strangely has a leak just under the expansion tank, might be the hose, might be the tank.................

[Laney760]

Cheers Dave. I will get the head gasket done at some stage but it doesn't seem to be quite the urgent issue I thought it was. I have another list of jobs to do before that, issues which were found at MOT today, all advisories but she did pass MOT. Spreading out the financial outlay! It all seems worth the expense except when I am having starting issues, then I feel like giving up the ghost!

[Laird Scooby]

Originally Posted by Laney760

Cheers Dave. I will get the head gasket done at some stage but it doesn't seem to be quite the urgent issue I thought it was. I have another list of jobs to do before that, issues which were found at MOT today, all advisories but she did pass MOT. Spreading out the financial outlay! It all seems worth the expense except when I am having starting issues, then I feel like giving up the ghost!

Congrats on the MoT pass Ellie, better luck than mine had!

In fairness i only had one advisory on an exhaust mount and the fail which is a small hole appeared in the wheelarch/footwell that i thought was mud not bubbly/rusty metal. To be honest, i couldn't see it properly until it was on the ramp so i wasn't too upset.

He nearly failed it on emissions too until i pointed out it was well within the limits for the year and didn't even have a cat so was doing well to be only just outside the limits for a cat-equipped car!

[360beast]

There is a metal pipe in the genuine header tank which expands with corrosion and splits the plastic where the hose goes on causing the leak.

The aftermarket ones don't have this so you don't have any risk of this happening again but I'm not sure if the plastic is as good as the original so I'm unsure of how long it will last. I've had an aftermarket one on mine since 2018 and done nearly 30k miles without issues so I expect they will last quite well.

[360beast]

Originally Posted by Laird Scooby

https://www.partsforvolvosonline.com...oducts_id=5755

That's the expansion tank Ellie, aftermarket but the OE numbers are listed below it. They used to sell the OE tanks as well but as they no longer do i'd make a guess they are NLA from Volvo but could be wrong.

As for the hose, there are two different ones available :

https://www.skandix.de/en/spare-part...-tank/1062295/

https://www.skandix.de/en/spare-part...-tank/1021196/

Both seem to fit strangely!

PS - just checked, the reason both seem to fit is one is genuine and the other is aftermarket, Volvo part number is 9155496 and just happens to fit my 760 too which strangely has a leak just under the expansion tank, might be the hose, might be the tank.................

Those hoses won't fit Ellie's unfortunately Dave as the turbo cars have another pipe that comes off of it to feed the turbo.

Like this one

https://www.partsforvolvosonline.com...oducts_id=8238

[griston64]

Originally Posted by 360beast

There is a metal pipe in the genuine header tank which expands with corrosion and splits the plastic where the hose goes on causing the leak.

The aftermarket ones don't have this so you don't have any risk of this happening again but I'm not sure if the plastic is as good as the original so I'm unsure of how long it will last. I've had an aftermarket one on mine since 2018 and done nearly 30k miles without issues so I expect they will last quite well.

Brookhouse sell genuine Volvo ones as I bought one a fortnight ago

https://www.classicvolvoparts.co.uk/...&Submit=Search