oil weight question

kw90supercoupe

kw90supercoupe

Registered User
Ok so my 90 supercoupe has had synthetic oil in it since she was young. But I have been puting 5w30 in it. The computers at advance says use 10w20. I have a verry verry slight almost knocking soundd only between 1200 and prob 1500rpm. Wondering what weight for synthetic are people usng? Motor was rebuilt this winter I don't want to mess it up again. Let me know
 
kw90supercoupe said:
Ok so my 90 supercoupe has had synthetic oil in it since she was young. But I have been puting 5w30 in it. The computers at advance says use 10w20. I have a verry verry slight almost knocking soundd only between 1200 and prob 1500rpm. Wondering what weight for synthetic are people usng? Motor was rebuilt this winter I don't want to mess it up again. Let me know
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I would suggest checking out the info at Bob Is The Oil Guy ( www.bobistheoilguy.com ).

From what I can suss out, a full synthetic 0W30, 0W40, or 5W40 may do better. However, don't blame me if 0W30 blows your motor ... it's just what I gather from reading! *grins*

RwP
 
kw90supercoupe said:
Ok so my 90 supercoupe has had synthetic oil in it since she was young. But I have been puting 5w30 in it. The computers at advance says use 10w20. I have a verry verry slight almost knocking soundd only between 1200 and prob 1500rpm. Wondering what weight for synthetic are people usng? Motor was rebuilt this winter I don't want to mess it up again. Let me know
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A knock around that rpm usually indicates a rod bearing but since you rebuilt yours this winter it's possible it could be something else. What was done to the engine during the rebuild?
 
Run 10W-30, lot of us will run much heavier 10W-40 to 15W-50. Put a real oil pressure gauge on and see what it is, and adjust oil weight accordingly.
 
I run 10w60 BMW syn in mine, I dont think I will do that again. I will switch mine to a 10w30 syn or 5w30 syn.

i used the 10w60 because it was free at the time because of collecting half quarts and such while doing oil changes on M3's
 
When i switched to synthetic, i have been using shell rotella T6 5w-40, no problems at all. and it comes in gallons so you can use your lucas oil treatment.
 
kw90supercoupe said:
What is the weight the 10w orf the 30?
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Neither. Both. Yes.

May I suggest OIL UNIVERSITY at Bob Is The Oil Guy ( www.bobistheoilguy.com ). He'll explain that neither is actually the WEIGHT, but the VISCOSITY of the oil - not quite the same thing technically.

As to which do you use - depends. Again, Bob explains it much better than I can in his university classes (don't scream - they're a web page long, each class, and each class, while sometimes snoozeworthy due to the details that MUST be presented, are WELL worth slugging through!)

RwP
 
kw90supercoupe said:
What is the weight the 10w orf the 30?
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The primary viscosity (thickness essentially) is 30. The 10 weight blended in is primarily for cold temperature startup. It flows easier and hence quicker to the bearings. As the oil heats up, it thins overall and frankly doesn't matter a whole lot in a passenger car.

BTW. If you hear a rod knock at certain rpms, its not the oil. Thats due to bearing clearance. When the oil gets into the bearings it will reduce the knock by reducing the gap.
 
kw90supercoupe said:
How about 10W-40 syn with that lucus oil treatment? The car has about 130,000 on it. Would that bbe to thick?
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I'd think so, but not sure.

Again, the BEST thing would be to refer to knowledgable people (Bob's about the best out there that's easily digested).

Again, I'd opt for a 5W40 or 10W40. If I used something like Motor Honey or Lucas, I'd think hard about a 0W40 for it, so that the oil ends up thin enough for cold starts.

However, disclaimer: If you do that and promptly toss rods out the oil pan, it ain't my fault. *grins*

RwP
 
Hevier is the best way 2 go with hi mileage

NO LESS THAN 10-30 FEEL 15-40 BETTER :rolleyes: THE NOISE U HEAR IS THE RODS KNOCKING BECAUSE OF WEAR ON THE BEARINGS AT BOTTOM END....IF U PUSH IT 2 HARD U CAN SPIN A BEARING!!!:eek: LOSE A ROD :(
 
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