x2 Mocal Oil coolers Burst!!!

[Blakefruid]

Hi All,

What would cause an cooler to split?
And how do I go about fixing it?

Sorry but this might be a bit of a long explanation of the circumstances and lead up, but the detail might help= or might be totally unrelated!
The bus has been really smokey (blue and sooty) and missing every now and then on start up for a while, but as soon as it warms up all is fine the smoke goes and the engine settles down.
We were on our way to Devon, all was well and the bus was happily sitting at 65. Then going up a long hill I had to change down to first to get to the top. As we reached the brow the over-heating light came on so we coasted down and the needle dropped- all was well. Then a few miles later it sounded like the exhaust was blowing, so pulled over to find pipe had snapped where it enters the back box. The bus was a little noisy and a little lacking on power up hills but still running fine. Camped for a week, and started the bus every now and then to charge up the leisure battery.

On the day before we left started the bus (from cold) and a couple of minutes later heard a gurgling noise and found oil dripping from the font mounted oil cooler (Brickwerks kit)- the bus hadn’t moved and there was no evidence of damage (I thought it might have been poked with something on the campsite).
So when we got home (RAC) I replaced the Mocal oil cooler, oil filter and oil (15 40 mineral) and due to the lack of power & smoke took it to a local ‘Diesel mechanic’ for a compression test- he could only get three injectors out (so an incomplete test) but they came back at 30, 30, 35 Bar.
So I’ve done about 40 miles on the new cooler, this morning started the bus from cold, and again almost immediately the new cooler had sprung a substantial leak. I sieved the last lot of oil thinking there might be metal shards that would puncture the cooler, but nothing.

So the question is what could have caused both the cooler’s to split?
And how do I go about fixing it?

Thank you soo much in advance,
Ian

[weimarbus]

I would suspect a stuck oil pressure relief valve, but no idea where it is on a diesel

[Blakefruid]

Thanks for your reply- yeah I was starting to think that.
But it does have a Mocal thermostatic take off plate, so I thought the oil didn't flow to the cooler till it had heated up, and this morning it burst very quickly- I'd be surprised if the oil was even warm.
Cheers,
Ian

[marlinowner]

The oil can always go through the cooler, the bypass closes when the oil is hot. My thought is pressure relief valve as well.

[Blakefruid]

brilliant, thanks for your reply!
any idea where i'd find the pressure relief valve on a JX?

[dave friday]

It's in the oil pump,at the top of the oil pickup tube,you'll have to drop the sump to get at the oil pump!
It might be an idea to buy a new pump....

[Blakefruid]

Thanks very much!