Oil cooler bypass - Massive oil spill

[simon291971449]

Hi folks. Bit of a disaster. Removed the oil cooler pipes from the filter housing, fitted the bypass loop with new o rings and the new longer stud which came with it. Got rid of all the old oil cooler gubbins. Brilliant, I thought. Started the car, and was about to get out to look underneath for any drips from the new bypass, when the car spewed litres and litres of oil onto the garage floor in about 10 seconds, from where exactly I'm not sure. It was far too much oil to have been just been the o rings on the new bypass, and it had definitely clicked into place. And I'm (pretty) certain there was no other pipe I'd disconnected and forgot to reconnect. If it's any clue, the oil had come out with such force it was all over the air filter and left side of the bonnet underside ie the top of the engine! One thing I should maybe mention. Before fitting the bypass, I pressed home one of the cylindrical junctions (with the o rings) into the filter housing to trial fit it. It clicked in nicely, and was a snug fit, but I couldn't get it back out ( I needed to remove it to get the original stud out). To get the junction out I had to put a hook up it's middle and pull downwards. I was aware the hook had initially gone up too far, and it felt as though it had impacted something (soft?) further up inside the filter housing. What's up there, and might I have damaged something up there with the hook? I suppose another alternative theory is that I accidentally dislodged/ disconnected/broke something vital to oil retention while working under the car (or while removing/pulling through the oil cooler pipes, which I'd had to cut). Perplexed! Grateful for any advice or theories on the carnage I've caused.

[JimMann]

Hi Simon, not good, but surely it can be recovered. From your description, you have disturbed something during your work that allows a full bore pressure outlet to the outside world - it has to be an "under pressure" escape for it to dump so much in a short space of time.

I am a great believer in the last thing(s) I touched are the most likely culprits for what has gone wrong and therefore I would strip and rebuild in the reverse order of what you disturbed to make the modification, ensuring that nothing else in the vicinity of the work site was accidentally disturbed, or broken - sometimes leaning on a component can cause a weak joint to fail. Obviously working on an oil cooler bypass means that a lot of oil is to flow in a very short circuit afterwards, so making sure everything is double checked is crucial.

Pretty sure more XJS specific advice will be along shortly.

Jim Mann

[PaulGover]

You didn't do something else such as an oil change, and forget to fit the oil filter? I once drained the sump and refilled days later, forgetting that I hadn't put the drain plug back
Otherwise I'd suspect a displaced O-ring. Under pump pressure, the small gap without one will leak like a sieve.

[poprivet]

One of these? (Random pic from internet)



Can only be a displaced O ring I would think?

[ptjs1]

Simon,

Don't be ashamed, you can admit that you didn't refit the filter if you want! We won't laugh, we've all done similar!

Joking apart, if you misplaced or distorted the rubber seal in the filter housing, it could dump the oil that fast. I once did similar on a TR6 when I fitted the new seal but hadn't removed the old seal.

Otherwise, I think it must be one of the bypass O-rings.

Good luck

Paul

[simon291971449]

Thanks all. Didn't think it could be just
an o ring, given the quantity and force of oil loss, but it does seem like the most likely cause. I'll pull it down and see if any of them have dislodged. As in the photo above, the old o rings I took off seemed more square in shape, and were like hard plastic. Was their shape and consistency just due to the shape of the channel they sit in, and their age? I've used straightforward round soft rubber ones to replace them. Any suggestions about how to insert the junctions without dislodging the o rings? Cover them in lots of oil? Thanks for ongoing help!

[ptjs1]

Simon,

I've got a new bypass kit at home. I'll get it out and take pics of the o-rings for you.

Paul

[JimMann]

Practically all O-ring's start off with a round section and after service end up taking the shape of the groove they have been working in, generally a square section, which is why they have to be changed after being disturbed as they will no longer provide an effective seal. Given that the O-ring should not be in contact with the fluid(s) they are there to retain within the system, it is practical to use a light smear of grease to retain the new O-ring in its groove during the rebuild process.
Jim Mann

[poprivet]

Are you sure the new O rings you used are the correct ones?
I suppose it could possibly be a split in the bypass casting.

[simon291971449]

Simple solution: I hadn't tightened the new longer bolt properly, so the by pass popped off when under full oil pressure. Doh! is the expression! All sorted now. Thanks for all your help, folks.

[ptjs1]

Good cheap result Simon!

And some new fresh oil is always good!

Paul

[SimonR]

Glad you got it sorted - I'm also glad this sort of thing doesn't just happen to me!