Expensive Lesson Learnt!

[chats]

Thought share my calamity........on advice from a supra veteran, used fully synthetic oil in my N/A JDM 1993 stock car and the rear engine seal leaking.......oil everywhere. Learnt that whilst fully synthetic oil great for lubrication, it ends up cleaning the carbon deposits around the seal hence the leak. Cost lot time and money and effort for that little poxy oil change!!! So beware...... unless you knew this already. Oh well c'est la vie... pardon my French!

[rider]

Seals also just fail. I had a pinion oil seal tear on my MGB. I'm sure that wasn't the oil that caused that. Threw the entire diff contents out. I was lucky the car only does 500 miles a year and I service/inspect it annually so it got caught in time before any damage occurred.

 

I've used synthetic oils in my Supra for over 20 years. Different synthetics. PAO's back in the early days then some ester blends and now highly refined mineral oils. The thing with engine oils is they are formulated to specifications and that includes detergency and elastomer swell specs so really it shouldn't matter too much which oil you swap and change to. Though, it is usually accepted as best to stick with one product. But even then over the very long life of these cars, that product formula will have changed even if the name hasn't; probably quite a few times. Best solution to that is to have bought a 205l drum of your favourite oil 20 years ago.

[chats]

Yes seals can go anytime. These engines were developed nearly 30 years ago without the synthetic oils of today. Going to stick to semi synthetic and same brand have been using without issues from now on.

[Mike2JZ]

Might be worth changing your other engine seals whilst you are at it. Personally I think the synthetic vs non synthetic is neither here nor there, however I frequently see the result of JZ engines that haven't had their seals changed in over 15 years.

 

Normally all the rubbers become brittle after many heat cycle, at which point seals start weeping or springing a leak.

 

If your rear crank seal felt brittle then chances are your front main, camshaft, distributor & rocker seals will be in a similar condition.

[Noz]

Always used 10w 40 on my NA. Fully synthetic.

 

Might just be luck rather than oil type.

 

Any chance you over filled and caused a pressure spike blowing the seal?

[chats]

Always used 10w 40 on my NA. Fully synthetic.

 

Might just be luck rather than oil type.

 

Any chance you over filled and caused a pressure spike blowing the seal?

 

 

Yes... guess it's bad luck. I did overfill but just marginally above top of dip stick mark. Thanks for advice.... will have a look at the rest of the seals.

[herbiemercman]

Good advice there Noz, I have always used FS oil, i was under the impression that it is essential when you have a turbo as you know the bearing temperatures are quite high and part synth is not suitable. From memory the oil seals are impervious to any oils and if anything they will swell slightly, bit like smearing the oil filter ring before you tighten it up. My big Merc estate has 265,000 miles on the clock and i bought it new in 1997, so the oil seals do a good job. Herbie.