Author Topic: When To Rebuild? (Read 2231 times)

busnerd · « **on:** September 27, 2005, 05:27:57 PM »

I have a '78 westfalia (auto) that I drive every day and it gives me no problems at all. However, a couple of times in the summer when in the interior (hot) after driving into a headwind on the highway for a long time (1.5hrs) then coming to a stop the oil light would flicker when in Drive (800rpm), but would go out when in neutral (925rpm). I know the owners manual says that the light may flicker after long stints on the highway, but it makes me uneasy. So I'm thinking worn bearings, and hooked up a mechanical oil pressure guage when hot and ran the engine at 3000rpm and had oil pressure around 25-27psi.

Is it time for a full rebuild?? or is it ok like this?

Bruce · « **Reply #1 on:** September 27, 2005, 10:36:27 PM »

Completely normal. Your engine should be good for another 50-100k miles.

What oil you running?

busnerd · « **Reply #2 on:** September 27, 2005, 10:55:20 PM »

20w50 penzoil

and the light never flickers around town or going up to whistler, or whiterock or any other time but super hot, fully loaded hill climbs and headwinds.

so you think it's ok for a while??

Bruce · « **Reply #3 on:** September 28, 2005, 10:29:29 PM »

Yep.

Next oil change go down to 10W-30. You don't want that thick stuff in there during the winter.

Shane · « **Reply #4 on:** September 29, 2005, 06:26:14 AM »

Re build when she shoots a piston

kirin · « **Reply #5 on:** September 29, 2005, 10:10:34 AM »

Amen!
Drive it till it blows.. But seriously though I'm of the opinion that if it is easy to replace and isn't obscenely expensive go till she breaks!

Cameron · « **Reply #6 on:** October 03, 2005, 10:23:42 AM »

How accurate is your oil pressure guage?
Do a compression / leak down test. That will tell you if the motor is worn.
Driving a motor until it breaks is a stupid thing to do. There are many reusable parts that are needed to do a rebuild. If you blow it up, it will cost you way more in the long run.

busnerd · « **Reply #7 on:** October 06, 2005, 05:38:43 PM »

I don't know how accurate the pressure guage was, I borrowed it and did not check it against any other guages. The motor has compression of 135psi across all four. Previous owner had a top end rebuild done by a shop in oregon when it dropped a valve on grant's pass about 17k ago. So it's got new heads but the bottom end was not done at that time. That's what gets me, the only thing that is apparently wrong with this engine is that the oil light flickers sometimes when super hot. I just want to know if that (assuming all else is good) is enough to warrant a rebuild??

Bruce · « **Reply #8 on:** October 06, 2005, 11:07:08 PM »

The flickering light at idle is perfectly normal and common. Even VW said it was not a problem. I've known several engines that flickered at idle when warm and they just keep going. If your oil light flickers only when hot, you're a long way away from a rebuild.

You should install an oil temp gauge since you are paranoid. When it gets too hot, slow down.

AlanU · « **Reply #9 on:** October 08, 2005, 10:35:41 AM »

Hopefully the mechanical oil pressure guage is accurate. I've used my SnapON guage and a cheapy chinese mechanical and both were spot on. Those pressure your getting are not that bad.

I have seen the oil senders to read inaccurately and cause a light to prematurely flicker.

If the engine feels strong doesn't consume alot of oil within a 5000-6000 km oil change interval I would just drive it happily. If you do have the time you can do a compression test just to see that all 4 are relatively consistant with no big differential in pressure readings. I've just spend just under 500 bucks on a snapon leakdown tester and they are not easy to use since the engine just turns over as you apply comressed air into the cylinder. Just do a compression test.

If you do want to improve oil pressure at operating temps I'd try a 10w40 multigrade and see if that helps increase the pressure when hot. This will have lower viscosity when cold and keep up a thickness of a 40 weight when hot.

busnerd · « **Reply #10 on:** October 08, 2005, 04:55:36 PM »

Thanks for all the input guys. I think I will just leave it for right now. Bruce your right, I guess I am paranoid..... my girlfriend has been saying that all along.

silas · « **Reply #11 on:** October 08, 2005, 05:54:56 PM »

Quote

I've just spend just under 500 bucks on a snapon leakdown tester and they are not easy to use since the engine just turns over as you apply comressed air into the cylinder.

engine in or engine out?

i seem to remember reading somewhere on the cal-look forum where a couple guys had adopted a method to overcome that.

iirc, what they did was remove the rear most engine tin, attach a 36mm socket (i cant remember the exact size) to the crankshaft pulley bolt, attach a long breaker bar the socket and wedge it against the floor after you find tdc on the cylinder that you're checking. i guess it would depend the header and muffler clearance tho.

if the engine is out, could you somehow attach a wedge type stopping device to the ring gear on the flywheel?

also, shouldnt you get about 10 psi oil pressure per 1000rpm? so busnerds initial reading of 25-27 psi @ 3000rpm isnt too bad.

someone please correct me if i'm way off base here.

AlanU · « **Reply #12 on:** October 08, 2005, 06:54:57 PM »

The oil pressure at 3000rpms isn't bad at all. Like I said drive it

Leakdown test in the car are a pain. The likelihood of rotation is high. The test indicates a more accurate diagnostic of the condition of the engine. For a water cooled car its great to test for headgasket issues since it'll bubble/hiss in the rad or just listen to the exhaust pipe or intake throttle body area to test the \"seal\" of the valves.

As for the oil pressure issue I'd leave it be. AS long as the mechanical oil pressure guage is concerned I'd say trust that guage and drive the thing.