V70 D5 top coolant hose popping off

[Simmy]

dont worry to much about hose temps if your car is not over heating just drive and monitor fluid level. iv not heard of any d5 head gasket fails. a kit to sniff coolant tank is available if you suspect hg failiure.

[cheshired5]

Originally Posted by chunky2778

temp never rises above 98 Deg C

That's still way too high.
Have you run a hose through every cooling system inlet/outlet?

[chunky2778]

Originally Posted by cheshired5

That's still way too high.
Have you run a hose through every cooling system inlet/outlet?

When I changed the thermostat I ran a hose through the thermostat housing hole with the top hose off, so it was reverse direction of flow, then through top hose until header tank filled etc.

It had a good half hours flush, everything came out pretty clean.

Once I purge air out of the system it's finding it's way back in after a few drive cycles.

The 98 Deg C was pushing it hard on the dual carriageway, 95/96 was cruising, then 90/92 is when thermostat opens at idle.

[chunky2778]

Originally Posted by Simmy

dont worry to much about hose temps if your car is not over heating just drive and monitor fluid level. iv not heard of any d5 head gasket fails. a kit to sniff coolant tank is available if you suspect hg failiure.

It's more that air is being reintroduced into the system that's concerning me

[cheshired5]

Originally Posted by chunky2778

The 98 Deg C was pushing it hard on the dual carriageway, 95/96 was cruising, then 90/92 is when thermostat opens at idle.

You have a 90°C thermostat so your maximum temperature should be 90°C.
Creeping up to mid 90s+ means that when the thermostat opens, the flow isn't pulling out hot coolant or allowing cooler coolant to circulate quickly enough.

I would run a hose forwards and backwards through both upper/lower openings on the radiator and remove the heater core connectors in the engine bay to flush the core.
I've cured a mildly overheating D5 just last week by doing the above.
It's free and worth a go.

Also consider pressure testing the cooling system.
I use my Sealey brake bleeder which fits perfectly on the expansion tank and pressurise to 12 psi which should be high enough to expose a breach. If there's a leak, the pressure reading on the bleeder will drop.

[stuart bowes]

I seem to recall reading someone talking about using a brake bleed kit on the header tank and getting air pressure up, watching to see if liquid comes out anywhere? (or seeing if the pressure drops which might indicate an air leak somewhere)

is that a thing people do or have I remembered incorrectly

==
oh ok dont worry see above, beat me to it
==

[chunky2778]

Originally Posted by cheshired5

You have a 90°C thermostat so your maximum temperature should be 90°C.
Creeping up to mid 90s+ means that when the thermostat opens, the flow isn't pulling out hot coolant or allowing cooler coolant to circulate quickly enough.

I would run a hose forwards and backwards through both upper/lower openings on the radiator and remove the heater core connectors in the engine bay to flush the core.
I've cured a mildly overheating D5 just last week by doing the above.
It's free and worth a go.

Also consider pressure testing the cooling system.
I use my Sealey brake bleeder which fits perfectly on the expansion tank and pressurise to 12 psi which should be high enough to expose a breach. If there's a leak, the pressure reading on the bleeder will drop.

Thanks Cheshire, I will try the things you've suggested when I get the chance, doesn't help it's dark so early at the moment.

Before I'd seen any responses, this afternoon I took it down to a friend's garage. He put the block tester on it but the fluid colour didn't change.

Pressure tested it, reading not dropping. He used an infrared temperature gauge, bottom hose is around 15/20 degrees lower than the top at idle.

There's no air in the system until car fast idled, then the return starts frothing, but never overheats. Once the froth is in the tank you can see quite large air bubbles being pumped into the header, and at his garage was the first time I've seen it do it while idling too.

Both heater matrix pipes run hot and never blows cold/loses temperature briefly.

He's suggested water pump, I did fit a new Gates one when I did the cambelt about 6 months ago, it's a metal impeller.

It just doesn't seem to have the symptoms of a blockage?

How do the heater core pipes come off please, is it a special tool/pliers to remove or do they squeeze?

Main thing is I'm struggling to trust the car now as I rely on it quite heavily, I have some videos and photos of what it's doing but the forum fails the upload them?

[cheshired5]

The heater pipes have a spring loaded collar which needs twisting to the left/counter-clockwise a quarter turn which will release catches and allow the connector to pull straight off without any special tools required.

As for videos, upload them to YouTube then post a link to the video.

[chunky2778]

https://youtu.be/tvyjsdPrPcQ

https://youtu.be/q4xey7sRFA4

https://youtu.be/LOmS5ZtLay8


If you wouldn't mind taking a look I'd be grateful 👍

The videos are a few days apart, sometimes coolant looks like it's not aeriated but usually ends up looking like videos.

[chunky2778]

So I had the matrix pipes off today and reverse flushed both the matrix and 10/15 mins through each matrix pipe so it either came back up through the header tank or through the top radiator hose.

It all looked really clean antifreeze in there but once connected back up and left to fast idle to bleed through, level dropped twice as air bled out then levelled out but temperature is showing anywhere between 96 to 103 Deg C.

Also once fast idling bottom hose goes warm but after driving it goes lukewarm/cold again.

On a run it settles at around 92-96 C and then if you put the power down it surges to 100 C then drops back.

After a run I let it idle in Tesco's car park for 5 mins and even with the fan on the temp rose to 103 and climbing.

Turn engine off, fan runs for 5 mins or so, temp dropped to 96 C then sat there for 10 mins or so.

Started engine, temp dropped to 89 immediately then started rising to 100 ish again.

If the water pump was weak/damaged it wouldn't circulate from the top return hose when held at fast idle would it?

Could anyone else tell me if their D5 circulates continually out the return hose please or only does it when warm and fast idling?