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oil temperatures on 1.9 DG

Posted: 25 Oct 2014, 21:06
by 123-jn
I have recently put a temp gauge (digital) on my oil system and it is interesting to watch. My engine is a 1.9 DG auto that has been rebuilt recently. I had noticed that my oil pressure would drop quite a lot when working the engine hard up mountain passes or fast on motorway runs. (I knew it wasn't bearing wear as I have just rebuilt the engine and clearances are all the better side of normal.) On getting out after a hard climb or run the engine always smelt very hot, I wondered if it really needed an oil cooler.
I decided to fit a small is 9 row cooler in the airflow next to the gearbox and run An8 hoses from a sandwich plate under the filter. I have an 80 degrees stat plate but haven't fitted it yet as the hose fittings are wrong and adaptors are needed, so for now it's a standard plate. Warm up time is about 1 mile longer (stat would help this) but on a normal run around A roads the oil temp runs at between 88 and 98 degrees centigrade, it never really goes outside these parameters. However if I do 60 mph or faster on the motorway it climbs to 106 degrees and has not yet exceeded a maximum of 108 on a steep incline foot to the floor. Welsh hill climbing on A roads takes it to the high 90's and max of 102 so far. This looks to me to be a pretty perfect set of temperature readings. It needs to be over 80 and should not regularly run more than 120 as far as I've been told (due to the mineral oil). What makes me think is what temperatures it was at before I fitted the cooler.(9 row cooler 12 inches long and 1.5 inches thick) Oil pressure now remains well behaved no less than 20psi at tickover and around 60PSI running at 60 mph on the motorway. The engine no longer smells like it's about to self destruct after a fast run. Does anyone have a DG with an oil temp gauge and no cooler?

Re: oil temperatures on 1.9 DG

Posted: 26 Oct 2014, 08:06
by ghost123uk
Interesting stuff there. I cannot help with figures as I don't have an oil temp gauge but I have often thought about fitting a cooler. I know they are standard fitment on the 2.1i engine. I wonder if many of our vans exceed that 120 degree figure you quote :evil:

I will be watching with interest for any replies to your question. (You could always by-pass your cooler for a trip or two ;))

Re: oil temperatures on 1.9 DG

Posted: 26 Oct 2014, 08:25
by 300CE
Have you got any pics of the fitment 123 as would be really interesting to see. In your opinion, do you also think a different viscocity oil would have made any difference to the temp readings for an engine under load?

Re: oil temperatures on 1.9 DG

Posted: 29 Oct 2014, 10:14
by kevtherev
I have a pressure guage and noted the consequential decrease in pressure as water temp rises.
The oil temperature is coolant driven that's for sure.

I have since moved from 15/40 to 20/50 and the pressures have stablised a lot.
I was thinking of fitting a cooler but the thicker grade oil has calmed the situation down.

Re: oil temperatures on 1.9 DG

Posted: 29 Oct 2014, 12:22
by 300CE
kevtherev wrote:I have a pressure guage and noted the consequential decrease in pressure as water temp rises.
The oil temperature is coolant driven that's for sure.

I have since moved from 15/40 to 20/50 and the pressures have stablised a lot.
I was thinking of fitting a cooler but the thicker grade oil has calmed the situation down.

Cheers for that Kev - interesting to know - which 20/50 are you using as the van is due for a service and i might pick some of this up. :ok

Re: oil temperatures on 1.9 DG

Posted: 29 Oct 2014, 12:50
by kevtherev
Morris oils...
But it was on offer at the last vintage bike show at £12, I generally use Halfords when it's in

Re: oil temperatures on 1.9 DG

Posted: 29 Oct 2014, 12:59
by itchyfeet
I moved to 20/50 two years ago when the buzzer would trigger when very hot, usually only when slowing down into a roundabout or similar, I tried 15/40 again this year but had the same problem so went straight back to 20/50

Re: oil temperatures on 1.9 DG

Posted: 29 Oct 2014, 14:18
by 300CE
Many Thanks chaps - will give the 20/50 a go. Was it the Morris Golden Film you used Kev as it seems you can still get this for a decent price.

Re: oil temperatures on 1.9 DG

Posted: 29 Oct 2014, 15:02
by kevtherev
Yes that's the one

Re: oil temperatures on 1.9 DG

Posted: 29 Oct 2014, 17:35
by Atomic
I use Valvoline VR1 20w50 mineral oil - made a significant improvement in hot oil pressures on our Beetle Cup Aircooled race engine, so use it on the 2.1 WBX Caravelle as well. About £25 for 5 litres off ebay but worth every penny in my book.

Re: oil temperatures on 1.9 DG

Posted: 29 Oct 2014, 19:18
by 300CE
Cheers for that atomic - looks like car parts 4 less are selling them for £25 so will keep that in mind as well :ok

Re: oil temperatures on 1.9 DG

Posted: 31 Oct 2014, 23:06
by 123-jn
I have to admit to using asda 20/50 mineral in mine and change it every 3000 miles (£10 for 5 litres), as for pics of installation I'll have to take some as I didn't when I fitted it.

Re: oil temperatures on 1.9 DG

Posted: 01 Nov 2014, 22:58
by Atomic
The other thing to consider is changing the thermostat. As you say, even on the 1.9 the oil temp is coolant temp driven. The VR6 thermostat is a direct swap and is a lower temp (80°c instead of 87°c). I run it in my 2.1 Caravelle (late cooling system) and the 2.2 WBX in my Beetle with early cooling system. Part 075121113D for under a tenner from VW Heritage. Bringing the coolant temp down has to benefit the oil temp and hence oil pressure.