Frankenmix catastrophe.

[TallPaul]

Originally Posted By: oilyriser
Did the noise sound like a heavy loose belt slapping against a plastic cover, by any chance?
Maybe it was a cat or squirrel being run through the pulleys?

 

[chevrofreak]

or stuck valves being bashed by pistons?

 

[bob_ninja]

Originally Posted By: demarpaint
I doubt mixing a 5W-20 and a 5W-30 hurt anything. I think the moly add finally caught up to him. IIRC he used the stuff for years, at least that's what I thought I read in his posts. I think a few frequent OC's and sticking with a factory blended oil vs the Frankenmix is in order.

Frank D


ditto

We have already established that xWy are very crude approximations of viscosity and that specific cSt values are the accurate measures of thin vs thick, concordantly what is appropriate for a given situation. If you read the many posts from Canada about starting car at x degrees (usually below 0F) than you should know that Scoobie and other Canadians drive in much lower temperatures now than during the summer.

From my limited reading I believe that most 5W20 oils have lower viscosity than most 5W30 oil even at 0F and lower. So even though they share 5 in truth 20s are generally thinner in most winter temperatures. Therefore Scoobie's thinking is 100% correct regarding using 5W20 to thin out the mix.

We also discussed how dumbed down manuals are these days. There are examples of manuals with many recommendations while most new manuals have no choices at all but either go with 5W20 or 5W30. Such a simplistic recommendation cannot be correct at the same time for -20F winter in Canada and +100F summer in Texas. Thus it is perfectly normal for Texans to go +5 or +10 (10W40 vs 5W30) and Canadians to go -5 or -10 (5W20 vs 5W30). Again, I don't see such an adjustment as a big deal to fuss about.

From my personal experience, I mixed 1qt of 5W20 with 2+qt of synth 5W30 (PP). I have a 2L engine turning steady 2K-3K light load so why not lighten my mix a bit? My temps are around -10F to 30F.

Regarding not mixing brands ...
It is difficult to avoid, at least for me. 5W20 and 0W20 are hard to find. Even 0W30 is tough to locate. So while I may have 5W30 PP, I could only get a Shell made 5W20 at a reasonable price.

Most oil makers have very similar formulas and many discussion in the past noted that it is very rare that additives between 2 brands may conflict. I also doubt that they would somehow cancel each other to any great extent. If that were the case then we would see a lot more engine problems from people mixing too much.

Of course, if possible I try not to mix different brands but often it is hard to avoid.

Anyway just wanted to help out Scoobie as I don't think he made a bunch of mistakes, only one really.

 

[scoobie]

Thanks for the comments guys, one more followup:

This morning it was close to 0F. Car starts like a shot, easier than ever, totally smooth, with absolutely NO start up noises.

thanks for the nice post bob_ninja. This Canadian Tire Formula 1
synthetic 5W25 is super nice for the Impreza, PLUS it's the cheapest synthetic in Canada, made by Shell, and it periodically goes on for GOOD sale price, and by the published viscosities will easily protect any engine, whether it calls for 20wt or 30wt. (of course use your judgement in summer, depending on load, driving style).

 

[oilyriser]

sticky timing belt tensioner