synthetic oil leak?

[ironmedic]

hey have any of u guys had an oil leak with synthetic oil? i know i have a bad rear main seal (which makes me put oil in my car more often) but i just changed the oil in my car like 2 weeks ago and my check oil light came on. i checked it and it was very very low. i havent done anything to my car other than an MSD 6AL box and that obviously didnt cause the problem. i looked all over for the leak and i dont see it.
could it be that it is synthetic? im using royal purple 5w30 if that helps.

 

[HISSIN50]

were you using the same weight of dino oil before?
the syn may be cleaning out your seal as you elude to. also, syn often burns more compared to a dino oil of the same weight.

keep up on the level and dont let it go too long. when i change over, i like to use a normal OCI for the first change (~3K miles) since the oil will have some crud in it (all the spring cleaning it has done). next change i run 5K (the longest i let any syn go). on the third change, id run it for whatever extended OCI you want.

my two cents. good luck.

 

[maverick0716]

It's very common that when you switch to synthetic engine oil in a high mileage engine, it will leak.

 

[89MustangGX]

If you were losing a quart fo oil every two weeks, you'd either see it on the ground or out your tailpipes -- regardless of type of oil. My guess is going to be more along the lines of not quite filling all the way/mismarked dipstick/malfunctioning oil sensor/etc.

 

[92GreenGT]

Worst mistake I ever done. When changing out my clutch, not replacing the rear main. I put everything back together and throw in some Mobil 1 synthetic, and guess whats leaking. Yep, the rear main, not to big of a deal but kinda ticked me off. Oh well, out with the tranny,bell,flywheel and clutch I guess.

Dave

 

[ironmedic]

my first oil i used was castrol non-synthetic 10w/30. i had no problems with it except that it goes through quarts every couple of months (cuz of the rear main seal).
i had a small puddle of my oil on the ground today when i moved my car but didnt realize it.

 

[The Shape]

It is different for everyone. Plenty of people change to synthetic and have no problems. When I changed over I did notice my rear main leak got a little worse, but it wasn't a big deal. Also the reason I switched is I wanted to run a heavier weight oil for pressure reasons, and the Mobile-1 15W-50 is supposed to flow just as well cold as conventional 10W-30. So to me it was worth putting up with a little more leaking for the more stable oil pressure as well as the added protection from synthetic.

 

[ironmedic]

yeah i hope this blows over and doesnt turn bad. im still pestering my wife about changing my tranny. im not gonna drop the tranny, change the seal, put it back on, then replace it again a month or so later.

 

[cevtv]

I have been running Mobil 1 synthetic 10-30 for the last 30,000 miles............I don't leak one drop.

 

[cmozez]

for one thing, 5w30 is to light for a high mileage motor. I have always used syn oil and in my experience, a motor will burn more syn oil than dino oil.

 

[ironmedic]

so do u think i should swap out to 10w30 synthetic? i was planning on running 5w30 for the summer and swap to 10w30 syn after september.

 

[ironmedic]

oh BTW i was reading something about the wrong oil and valve train noise. i really dont think i have valve train noise but when i tach my car up to 2k i hear this ticking noise (very low). at idle i hear nothing. i changed my header gaskets cuz i thought they were trashed (they were anyways) but it didnt fix. think oil has something to do with it?

 

[maverick0716]

so do u think i should swap out to 10w30 synthetic? i was planning on running 5w30 for the summer and swap to 10w30 syn after september.

If anything, it should be the other way around. You want the thinner oil for the winter and the thicker oil for the summer.

 

[ironmedic]

yeah i just read that. i spoke with a couple hot rod shops here and they said 5w30 royal purple is fine to use during the summer here in WA. one guy told me he uses it in his 180k mile impala SS and has never had a problem.

 

[HISSIN50]

it is hard to get a definitive answer on it. generally you want the thinest oil that you can keep hot idle pressure with. if you can get away with a 5W-30, go for it. but if you try it and your hot pressure sucks, bump it up.

that said, i tend to like more viscosity, but Wa state has moderate temps, so a 10W-30 should be fine (or 5-30 in winter)....and syn gives you a lot more 'cushion' in that regard.

my two cents worth.

 

[89MustangGX]

I run 5w30 Mobil-1 year yound -- and even though I'm new to this coast -- I see no reason to change.

 

[408stroker5.0]

5W50 seem's like a good way to go.