V70 2.5 TDI 1997 workshop manual

[NI_Volvo_Nut]

To flush - if I were doing it....

Remove top hose at the radiator, remove the thermostat, connect garden hose and and go for a cuppa.

Fit new thermostat, drain radiator, refit all hoses, add 3 lts of concentrated coolant and top up with water.

[Aubergine man]

Thanks Bob! I've drained the coolant (by removing bottom hose) and put water through the system. Problem is only very little water has come out or gone back in (at a time I mean). It only drains as far as the expansion tank emptying but I can still see water sitting in the pipe at the bottom if the tank which makes me think most of the system sits higher than the expansion tank (but that doesn't make sense visually!)
if I put the hose back on and fill expansion tank with water I only get about a litre in which suggests to me that there's an air lock somewhere or something not working right. I've run the engine (idling) for a little bit with the expansion tank lid off and there seems to be some circulation of the water.
Other thing I've seen in a couple of videos is to remove the thermostat to let water through whole system. Do you advise for or against this anyone?
Thanks

[Aubergine man]

Right ok thermostat then. Grand I'll get on that now. So if I'm following your instructions then ni volvo nut I don't need to start the engine is that right?

[Bob Meadows]

Yes you can remove the thermostat to aid flushing but not always necessary- for the cost of them they are worth changing.
The two screws can be a real pain to remove on some cars- leave the screws soaking in your favorite releasing fluid for as long as you can, use a descent tool to stop the heads rounding off and go easy to avoid breakages. These can be be replaced with hexagon head stainless for next time!
Done the above last year and had no problems but some owners do.

From what you describe it is difficult to diagnose remotely- you can check the radiator as a separate item just to see what the flow rate is like and maybe eliminating this?
For air locks try raising the front of the vehicle as you bring the temperature up- heater fully open.
Good luck.
Bob.

[Martin Cox]

The thermostat on the Tdi engine (D5252T) is not at all easy to get at.

I believe it's fitted in the housing where the bottom hose joins the block. If it's working properly, I'd be tempted to leave well alone.

After 22 years and 227,000 miles the thermostat on my Tdi still seems to be behaving itself so I've left it firmly alone. Obviously if yours is giving trouble, then that's a different matter.

It's worth using genuine Volvo Coolant because, barring leaks, you'll never have to change it again.

As an aside, the 850OBD2 app for Android phone and a suitable Bluetoooth dongle is worth investigating. It will allow you to read many of the codes since the early V70s are not OBD compliant and generic code readers won't touch them. It will also allow you to read live data and in particular it should allow you to check the dynamic pump timing. Injection pump timing on these engines is critical. The app is less than £2 and a proven dongle is about £20.

Martin

1998 V70 Tdi auto 227,000 miles

[Aubergine man]

Yes Martin I was coming to that same conclusion myself about the thermostat it's in such an awkward place to be able to get to the bolts! And good tip for the phone app thingy, do you know if it works for the 1997 model? Is that all I would need for diagnoses (app + dongle)?
I've already bought some comma super long life coolant so prob won't get the volvo stuff now. Also timing belt will need done if I can sort other problems first which I'm told means a water pump change which will mean draining the cooling system too (I think)
Water seems to be flowing through the radiator fine I think the blockage must be somewhere else. I've asked my mechanic friend to have a look tomorrow so hopefully we'll get to the bottom of it then.
Does anyone know how to change the title of this thread in case someone else has similar problems? Lots of great info here so be good to make it findable!
Thanks everyone!

[Martin Cox]

I believe the app was written for the 850 series cars but it will work on the earlier V70s and S70s too. It works well with my 1998 V70 (MSA15.7) Tdi so I think it should be fine with a 1997 model.

Martin

[Luxobarge]

Originally Posted by Martin Cox

the early V70s are not OBD compliant

Not necessarily, my very early 1997 V70 T5 works fine on a generic OBDII reader (Autel Maxiscan MS501) although that's a petrol car, I guess it may be different for the diesels? Having said that, when I got mine the dongle solutions weren't so good or readily available, if I were doing it again I'd go the dongle route anyway I think.

Cheers!

[Martin Cox]

Many thanks Luxobarge, I stand corrected. I've no wish to propagate mis-information.

I never tried a generic code reader with my V70 since the received wisdom was that it wouldn't do anything useful. What I should have said was that I believe the early V70s may not be fully OBD compliant.

Martin