V50 D3 Coolant issues, possible head gasket failure?

finhudson16 · Aug 23rd, 2020, 13:55

I'm after a bit of advice about a problem I'm having with a V50 D3 I've just bought. I bought it with a suspected coolant leak and I've narrowed it down to coolant escaping through the vent on the cap while it's being driven. I've pressure tested the system and the cap works perfectly, it vents at 20psi as it should.

Even after it's cooled down, the system is still pressurised and bubbles up a bit when you remove the cap; given this I suspect that the problem is something over pressurising the cooling system while it's running, causing the coolant to bubble up in the tank and escape through the cap, which is venting due to the increased pressure.

Has anyone got any experience with failed head gaskets causing this? I've got the D3 5 cyl engine which I believe is a de-stroked D5 engine. Parts are really hard to find for the D3 so I'm hoping it's not anything more serious like a cracked block for example.

Does anyone know if there's any parts compatibility between the D3 and D5 engines?

I'm new to volvos here so any knowledge/common faults with these engines would be really appreciated!

finhudson16 · Aug 25th, 2020, 17:28

Well the plot thickens now and I'm very confused. I borrowed a combustion gas tester from a friend and I could see gas bubbling through it (gas escaping the expansion bottle) when I let off, but the gas doesn't contain CO2 as the tester stayed negative for the whole time so I don't think it's a head gasket or cracked head/block. The tester definitely works fine, I exhaled through it and it indicated CO2 immediately.

It looked like it was drawing air in when I increased the throttle and air comes out when letting off - is this normal?

Still not fully convinced it's not a head gasket/cracked head or block because a crack could only open up at high load, does that seem reasonable? I did rev it pretty high and for quite a while though and no combustion gas indicated.

Would it be possible for a faulty water pump to draw gas into the cooling system? I'm stumped as to what it could be if not combustion.

Does anyone know anything else on these engines that can introduce gas into the cooling system?

Thanks

finhudson16 · Dec 23rd, 2020, 16:55

Just giving an update in case anyone was curious or has the same problem - it was a very slightly warped head causing the head gasket to leak at high loads. A head skim and a new head gasket and bolts and it's all sorted! I believe that a tiny spot on the head gasket failed, creating a big air bubble and a hot spot on the bottom of the head, warping it and causing more leaks. Either way, it's fixed now and I love how it drives!

Leeg27 · Oct 27th, 2021, 19:15

How much did it cost you to get it sorted if you don’t mind me asking ?

Aug 23rd, 2020, 13:55	#1
finhudson16 New Member Last Online: May 29th, 2023 21:40 Join Date: Aug 2020 Location: Malmesbury	V50 D3 Coolant issues, possible head gasket failure? I'm after a bit of advice about a problem I'm having with a V50 D3 I've just bought. I bought it with a suspected coolant leak and I've narrowed it down to coolant escaping through the vent on the cap while it's being driven. I've pressure tested the system and the cap works perfectly, it vents at 20psi as it should. Even after it's cooled down, the system is still pressurised and bubbles up a bit when you remove the cap; given this I suspect that the problem is something over pressurising the cooling system while it's running, causing the coolant to bubble up in the tank and escape through the cap, which is venting due to the increased pressure. Has anyone got any experience with failed head gaskets causing this? I've got the D3 5 cyl engine which I believe is a de-stroked D5 engine. Parts are really hard to find for the D3 so I'm hoping it's not anything more serious like a cracked block for example. Does anyone know if there's any parts compatibility between the D3 and D5 engines? I'm new to volvos here so any knowledge/common faults with these engines would be really appreciated!

Oct 27th, 2021, 19:15	#4
Leeg27 New Member Last Online: Jan 11th, 2022 05:24 Join Date: Oct 2021 Location: Liverpool	Hi same issue on a d5 How much did it cost you to get it sorted if you don’t mind me asking ?

Aug 25th, 2020, 17:28	#2
finhudson16 New Member Last Online: May 29th, 2023 21:40 Join Date: Aug 2020 Location: Malmesbury	Well the plot thickens now and I'm very confused. I borrowed a combustion gas tester from a friend and I could see gas bubbling through it (gas escaping the expansion bottle) when I let off, but the gas doesn't contain CO2 as the tester stayed negative for the whole time so I don't think it's a head gasket or cracked head/block. The tester definitely works fine, I exhaled through it and it indicated CO2 immediately. It looked like it was drawing air in when I increased the throttle and air comes out when letting off - is this normal? Still not fully convinced it's not a head gasket/cracked head or block because a crack could only open up at high load, does that seem reasonable? I did rev it pretty high and for quite a while though and no combustion gas indicated. Would it be possible for a faulty water pump to draw gas into the cooling system? I'm stumped as to what it could be if not combustion. Does anyone know anything else on these engines that can introduce gas into the cooling system? Thanks

Dec 23rd, 2020, 16:55	#3
finhudson16 New Member Last Online: May 29th, 2023 21:40 Join Date: Aug 2020 Location: Malmesbury	Just giving an update in case anyone was curious or has the same problem - it was a very slightly warped head causing the head gasket to leak at high loads. A head skim and a new head gasket and bolts and it's all sorted! I believe that a tiny spot on the head gasket failed, creating a big air bubble and a hot spot on the bottom of the head, warping it and causing more leaks. Either way, it's fixed now and I love how it drives!

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