I’ve had my E-Type, 4.2 engine, 50+ years and never had this happen before. Cruising around yesterday, scanning the gauges I see oil pressure down to 5-10-20. Coming to a stop, it goes up to normal 40-50. Engine running fine, I check oil level, it’s lower but still in the hash marks on the stick. Add oil, go out after about an hour and it starts doing it again. Up and down. Scary! Anybody got any clues to this disturbing situation? Thanks HB
Hi Howard,
Is your’s an electrical or mechanical gauge?
Chris
Assuming gauge and sender are ok then a stuck pressure relief valve?
Les, Thanks for your response. I’m not much of an engine guy. Other than the gauge possibly being “toast”, but for my edification only, are the sender and pressure release valve potential engine damaging issues? Do either of those two functions affect the circulation of the oil within the engine, not to say I’m going to be driving the car until it’s fixed! HB
I doubt you have an internal engine problem. Most likely it’s the electrical sender as they are notoriously unreliable. If you want to be sure install a mechanical oil pressure gauge. Or you can buy a new sender and take your chances.
No to the sender, it’s just part of the monitoring system, but the pressure relief valve allows oil to bypass going into the engine and passes it straight back to the sump. Sometimes it can get stuck open due to junk getting stuck in there. It’s located near the oil filter and can be removed and cleaned.
If you have a manual it will tell you all about it in there.
Easy job for your mechanic assuming he knows what he’s doing on these engines. Shouldn’t cost much to do either…guessing, maybe an hours work?
As others have suggested I’d try a new sender first, they are quite unreliable, and see if that effects the symptoms. It’s easier to do than the relief valve, but if the sender doesn’t sort it out then I think I’d go for the valve.
When was the last time you changed your oil filter? If that gets clogged it will bring the bypass valve into operation.
Actually, if the filter gets clogged, another valve (referred to in the Service Manual as the Balance Valve) opens, and oil is passed unfiltered to the engine through the usual galleries. It is not bypassed to the sump. Still not a good thing, but at least the bearings get oil, though unfiltered.
David, Thanks for the info on the Balance Valve. I have two NAPA spin-on filters on the car that have only 2-3k miles since last oil change, so I don’t think that is the issue. In talking with Dick Maury and with info from others, I’m replacing the sender first. The sender unit has been in place for alot of years
David, I have a question for you. Have you ever been a vendor of Jaguar parts at shows at Carlisle etc.? Your name seems familiar in that respect. HB
Not me. I long lost relative perhaps… 