"Radiator" pressure cap for Yamar 4JH4E

Does any one know the pressure rating for the pressure cap on a Yanmar 4JH4E diesel engine?
The Yanmar spare list it at around £50.
It looks very similar to a standard car radiator cap.
If I know the pressure rating, I can probably source one for a fraction of the Yanmar price.
The current cap is original from 2007 and the seal is stuck, I can undo the cap, ie rotate it until it's loose, but I can't remove it.
Before I apply some brute forced, I'd like spare to hand, just in case I knacker it.

They are often marked with the pressure , either in bar or in psi or both but ITYWF you will also have to match the length..

Yanmar prices in the UK and Europe are a joke. As the other posters have said, it should be marked. I would make two wooden wedges and tap them under the 'ears' and force it off. A smear of special rubber grease should fix it.

Some years ago I paid - no option, needed it quick - £345 for a simple four cylinder head gasket for our Yanmar 4JH4-HTE.

Subsequent investigation leads me to believe my Yanmar engine is based on a Toyota block. A Toyota head gasket would be under £100.

This, however, pales into relative insignificance. Our boats upholstery is covered with the most excellent material from the USA with the trade name 'Ultra Leather. Needing three metres, we enquired price and availability from the UK Ultra Leather supplier.

£711 !!!!! First mate found an almost perfect colour match, 38 quid delivered. That is more like it.

Gearbox dipstick for a 3JH - £58; unbelievable but true.

Ian_Edwards said:

Does any one know the pressure rating for the pressure cap on a Yanmar 4JH4E diesel engine?
The Yanmar spare list it at around £50.
It looks very similar to a standard car radiator cap.
If I know the pressure rating, I can probably source one for a fraction of the Yanmar price.
The current cap is original from 2007 and the seal is stuck, I can undo the cap, ie rotate it until it's loose, but I can't remove it.
Before I apply some brute forced, I'd like spare to hand, just in case I knacker it.

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This one from Parts 4 Engines .......... £10

• Equivalent to Yanmar part number 129673-44131

Yanmar 3JH and 4JH Series Header tank cap

.

Thanks Vic,
I've ordered the part.
£10 is much more reasonable than Yanmar's £50+
I'll try levering it off as suggested, I didn't want to get stuck, with a non functioning engine, for the sake of some thing as simple as a pressure cap.

Robih said:

Gearbox dipstick for a 3JH - £58; unbelievable but true.

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And astonishingly, if they are similar to the one for a 3GM, the plastic they use for the top is attacked by gear oil! When I saw their price I made do with a bodged up repair

vyv_cox said:

And astonishingly, if they are similar to the one for a 3GM, the plastic they use for the top is attacked by gear oil! When I saw their price I made do with a bodged up repair

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Yanmar's dipstick is, as Vic says, soft rubbish and tends to keep breaking.
Cariblue Marine do very nice alloy replacements with the proper vent hole etc. Having extracted the remains of my (inherited) gearbox dipstick I used one of these and am pleased with it - also very nice to deal with.

Poecheng said:

View attachment 176503View attachment 176504

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Looks like we need a UK importer and reseller. You’d think someone would have picked that up.