Severe Oil Leak, Help Please asap

[ashleywakeling]

Hi there everyone, I have now owned penny for 18 months and lately have noticed severe oil loss... Started after i went from Maidstone to Whitby and back in 2 days and its got progressively worse since. I travel between 55 and 65 mph on average. Ive cleaned up the engine and the oil appears to be dropping beneath the engine and gearbox line, and also further back on the gearbox (i know my gearbox drips so thats not the issue). I did a journey to Hampshire and back (200 miles) and lost from max to well beneath empty on the dipstick. I have checked the breather and it is completely clear, any ideas? because im completely stumped, its as if something is pressurising somewhere. Everything by the HT side is completely dry also, and the head gasket line is also dry, im beginning to suspect the sump gasket? but it doesnt seem to be coming out of here, the oil pump is not leaking as i turned the tickover to 2500rpm and ran the engine for half an hour to see if itd drip, it didnt, no more then anything thumb nail sized, which is to be expected for an engine thats done 308,000 miles now without a rebuild. Thanks guys any help is appreciated

[aupickup]

possibly burning oil

[bmcecosse]

The oft described test is .....engine idling hot - remove the oil filler cap and rev up - is there a plume of smoke /fume?? The oil will be escaping from the labyrinth at the rear main bearing. Caused by combo of wear in the bearing and pressure in the block forcing the oil past the labyrinth... You must NEVER let the oil level dip below the minimum marking....

[JOWETTJAVELIN]

engine thats done 308,000 miles now without a rebuild.

That's really impressive mileage. I doubt sump gaskets would be the cause of so much oil loss without first coming to your attention - there would be quite a pool. Check how badly it leaks. Does it smoke? As others have said, if you're burning oil it will be empty in no time, especially at higher revs.

Check also for oil film on the engine which could point to, say, the rocker gasket where it weeps out then evaporates/burns off the engine.

Anyway it won't live on forever so I'd be saving up for a rebuild, hopefully after which it'll do another 300,000 miles!

[ashleywakeling]

After it ran for about 20 minutes i revved it HARD, foot to the floor and it smoked slightly, very very pale blue, but just one plummb of smoke and nothing more, i believe to just be oil thats escaped past the piston rings and sitting on top of the pistons?

[JOWETTJAVELIN]

Take it easy on an old, worn engine. Sounds not to be smoking too badly so the rings may be OK. The best test is when going down a hill, with the car going along in gear and not touching the accellerator, look in the mirror at the bottom of the hill when pulling away - how much (if any) smoke do you see?

But - you are obviously losing a hell of a lot of oil from somewhere - prepare to rebuild/replace the engine.

[bmcecosse]

The plume of smoke test is from the oil filler hole in the rocker cover.........

[JOWETTJAVELIN]

Oh...

[ashleywakeling]

Thanks for your help guys, no smoke in either of those instances, so im pretty sure its a leak not a burn... really quite worried, did 30 miles today between 20 and 40mph, and theres 3 hand sized puddles under the engine now :/ im possibly taking the engine out and inspecting the oil thrower?

[daveyl]

If it leaks from the front then timing cover and/or oil seal, perhaps. If it's the exhaust side, look at the two tappet covers and possibly the outlet pipe that is attached to one of them.

Rocker cover outlet pipe to carb/air filter? If as said, there is a lot of engine pressure.

[bmcecosse]

" im possibly taking the engine out and inspecting the oil thrower " What oil thrower?? If it's leaking from the rear main - the problem is worn bearings and/or pressure in the block. And yes - it's important to ensure the breathers are clear and connected to the carb or inlet manifold. Otherwise -an engine overhaul is the answer.

[simmitc]

Just an off-the-wall thought: Is the drain plug OK with a good washer? I have seen oil from here get blown backwards by the slip stream and appear to come from the backplate.

[ashleywakeling]

Having her up on a ramp tomorrow and proper good look, should reveal all i hope

[RobThomas]

Oddball question. Is there a rust hole higher up on the sump?

Most likely, as previously mentioned, that the rear main beraing has worn so much that the crank now whips round and scuffs the scroll on the back of the crank. This'll increase the oil flow rapidly. On a 1275 Lenham Midget a few years ago I broke a rear main bearing cap bolt and it showed me by dropping the sump contents in about 10 miles (on the M5) due to the tail of the crank whipping about and destroying what little 'sealing' there was.

[chickenjohn]

My first thought is to simply check the sump plug is tight and not leaking and ditto the oil filter- simple things first. Other than that, check the breathing of the engine as pressurisation from lack of crank breathing may be forcing oil out of the rear of the crank into the bell housing.

[bmcecosse]

Clean it all thoroughly - and then decide if the leak is IN FRONT of the backplate (= sump gasket problem) or on the BACK face of the backplate/from the jiggle pin (= rear main problem)

[lowride stepside]

my fing cracked an oil pipe feeding the oil pressure guage just behind the oil filter it [Don't swear or you will be banned - Admin] out scared the datsun cherry out of me , nice easy fix though

[ashleywakeling]

Okay, after looking at it up on the ramp, its over pressurising, and chucking it out the back via the main bearings... drilled two holes in the oil filler cap for more breathability and has improved slightly. Think the engine is just KNACKERED :L

[bmcecosse]

Bad move with that drilling - you are now breathing carcinogenic fumes....... You need to make the engine suck away and burn it's own fumes....

[chris_bates]

I agree it is likely to be the rear bearing assembly but someone did mention to me that sometimes oil can leak from the oil pump cover in the backplate. When I rebuilt my engine recently, I made sure the gasket was well "blued"! Worth checking all the bolts between engine and gearbox. If any have worked loose, it may indicate loose bolts securing the backplate to the engine block.

Chris