Hi guys. New to the forum with a bit of an OT question; hope you can help. I am attempting to use a Volvo sourced coolant expansion tank in a custom application on my vintage `69 Lotus Plus 2. Ideally I would like the relieving pressure of my cooling system to be between 7 and 15 psi, which is where the Lotus Twin Cam is happy.

The expansion tank is a flat looking affair, with (I think) OEM part number 463604 or 9142000. The tank looks like the one on the allautoparts.ru site with their part number 51.2000. I believe the compatable expansion cap has a M45x3 thread; the one I presently have is rated to relieve at 1.5 BAR, 21.75 psi, 150 kPa. The caps appear to be common across a wide variety of Volvo models circa 1986 to 2000`s. They appear to be available in various colours, but not sure if this relates to their relieving pressure.

I saw some similar looking caps on a British eBay site with 0.5 Bar and 0.75 Bar, but not sure if these fit or not.

Questions:

Is there a compatable cap that will relieve at a lower pressure available.
If so, what pressure.
What would be a part number or at least a Volvo model call-up I could use to find the available cap.

Thanks in advance. Hope I picked the correct model forum.

Volvo content: The Lotus uses similar carbs to the Volvo 122

Stu
Calgary Alberta

 

Yes, the colors are related to pressure.
If the threads are correct you would want the green one.
http://www.ipdusa.com/Volvo-940960/H...p-136-274-418/

 

Thanks Phil for the link.

The two caps shown look like what I need size wise.

Just to confirm, the green one (150 kPa - 1.5 bar - 21 psi) is what I have now. Looks like the black one (75 kPa - 0.75 bar - 10.9 psi) is what I need. The Lotus TC stock pressure range is I believe 7 to 12 psi.

Is the black one's part number 1357775 a dealer part number? I suppose the local dealer would find one if I specify for a 1985-1995 940 model?

Thanks again.

 

If you give the dealer a year, model and engine they should be able to look it up.

 

The colors don't always match the pressure ratings... I have a black and a grey at 150lbs... first two I looked up.