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Discussion Starter · #1 ·
I haven't found any real confirmation that the oil pan on 3.0 12V 164 would be removable while engine in place. I took a look under the car and it sure looks plausible, has somebody tried to remove it?
 

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I did that on a 155 V6 once and it wasn’t easy. Never looked at the 164 with that task in mind though. What’s the issue you’re investigating?
 

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Discussion Starter · #3 ·
Oil pressure drops to zero (according to the gauge) on idle and the warning light illuminates. The main suspects are either main or big end bearings… or both. I have done this job to a Saab recently, and the symptoms are exactly the same.
 

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That was why I did the 155, combined with a heavy bottom end knock, when it was hot, on overrun. Found big end shells to be worn, although not horrendously. Mains were good. Sadly, the repair didn’t last very long, suggesting that the crank was out of spec wear too. I did ‘plastigauge’ the clearances after putting the new shells in and they looked good, but I suspect the journals were out of round, which I couldn’t assess in situ. I’d be surprised if just new shells solve the problem for long, sadly. You also have the problem of figuring out what sizes you need. That can be hard enough even in the best conditions.
 

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Discussion Starter · #5 ·
Maybe I just have to start fiddling around to get the pan off. Removing sure seems possible in place but never know. Hopefully new shells work for me. Engine sounds just normal even with the light on, no knocking or rattling nor anything else, just the light after a while of running.
 

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Maybe I just have to start fiddling around to get the pan off. Removing sure seems possible in place but never know. Hopefully new shells work for me. Engine sounds just normal even with the light on, no knocking or rattling nor anything else, just the light after a while of running.
Although the gauge and the light agree, if there is no knocking, I think I would be inclined to unscrew either the light switch or the gauge sender and fit an adapter in there temporarily, just to put an old-fashioned mechanical oil pressure gauge on to it to make sure you really DO have an oil pressure problem first. It might save you a lot of work!
 

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Discussion Starter · #7 ·
Yep, I sure would like to know how much does the oil pressure actually drop. Isn’t the light sender threshold quite high on these?
 

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The oil pressure warning light will come on at virtually 0 psi/bar. As stated, first thing to do is connect up a known good pressure gauge and check actual pressure. I had a 164 TS years ago and the oil pressure gauge always read 0. Then the oil pressure warning light started coming on as soon as the engine warmed up. I connected a mechanical gauge and started the car and the gauge went off max scale at idle (more than 80 psi), so there was more than enough oil pressure, just the senders (both) were no good. Car ran fine for years with the light on.

On the V6 you can get the sump off but it's not particularly easy.
 

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Discussion Starter · #9 · (Edited)
Time has passed but if (and when) someone is looking this information, I'd say the sump can be taken out in situ. I ended up taking the whole engine out (dropped the subframe which is very easy if hoist is available) and I'd say it's worth the effort depending on what has to be done behind the sump.

Tips: There's two or three bolts behind the engine support bracket so that has to come off along with intermediate shaft.
Drain gearbox oil.
The engine must be lifted relatively high to get the sump out. Beware of the brake booster hose and power steering pump pulley.
Engine mount nuts (to subframe) are 17mm A/F. Take those out.
Sump bolts are M7 bolts with 11mm A/F. Couple with 13mm A/F.
 

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Discussion Starter · #11 ·
Worn crankshaft. Something had happened (don’t know if PO had no oil or what) but clearly someone had already changed big end bearings and main bearings but the crank had took a serious hit. I had it ground 0,25mm and resurfaced.
 

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They can sometimes be a bit thirsty on the oil and catch people out, leading to oil surge & starvation.

Glad you sorted it though.
 

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Discussion Starter · #13 ·
What is baffling me about this is that the big end journals were intact. I would have believed those are the first to take the hit. Maybe the wider clearances made them more resilient or so…

Btw, I took the engine out again and it was done in about 2 hours. Dropped the whole package along with the subframe, very easy.
 
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