I put in synthetic, now I have a leak!

[WhatMeOil]

Hello all, I'm new to the board, wish I would have found you before I did this.

I recently purchased a 1969 Full size Oldsmobile with about 60k original miles. (It's a 455 4-bbl.)

The previous owner lived in a warmer climate and told me he used straight 30 weight regular Valvoline. Over the first couple of weeks I had it, it never leaked a drop.

Fall is coming and I love the longer oil changes I get with synthetic on my newer vehicles -- so I did my first change with Valvoline SynTech (full synthetic) 5w-30 Oil and a Wix filter. A few days later a noticed a couple of small oil stains when the car was parked overnight.

From what I have gathered on this board, the leak(s) was(were) already there but the heavier oil was gunked up enough not to drip.

My questions are:
1) Did I do the right thing switching over to synthetic or have I opened a big can of worms?
2) If I switch back to standard oil with the leaking stop?
3) Should I just change the necessary gaskets and keep the synthetic?
4) Will the synthetic cause any other internal issues?

Thanks in advance for all of your help, as a newcomer to the site it really is hard to take it all in! (you guys really get into knowing about oil!)

--
Jack

 

[PhoenixTL]

Sorry to hear about your problem....

Try an Auto-RX treatment....

 

[sciphi]

Monitor the leak. It's not unheard of to have an older engine leak or consume some synthetic oil when it's first put in.

I'd be more worried about flat tappet (if this is a flat tappet engine) lifter wear than a small leak right now.

And, I'd think about running a HDEO like Rotella 10w-30 for the extra anti-wear additives not present in most car engine oils today. The engines of today don't need those as much due to better metallurgy and construction. Your beast might possibly benefit from them.

And, welcome!

 

[exranger06]

Originally Posted By: WhatMeOil


From what I have gathered on this board, the leak(s) was(were) already there but the heavier oil was gunked up enough not to drip.

My questions are:
1) Did I do the right thing switching over to synthetic or have I opened a big can of worms?

There's no reason to be scared of synthetics. Aside from loosening gunk and revealing leaks, it's not gonna do anything bad to your engine.

2) If I switch back to standard oil with the leaking stop?

Probably not.

3) Should I just change the necessary gaskets and keep the synthetic?

Yes, change the gaskets, and then use whatever oil you want, conventional or synthetic. Either way, it won't leak any more because you replaced the gaskets. Remember, the syntehtic didn't really cause the leak, it just made an already bad gasket more apparent. So, replace the gaskets and you'll be good to go.

4) Will the synthetic cause any other internal issues?
No, absolutely not.

 

[chubbs1]

First off, WELCOME to BITOG! Next I don't think you opened up a can of worms with the syn. I would try to find the site of the leak and fix it if you can. It gets cold in Reno straight 30 is too thick, so don't go back to that. If the leak is really bad and you don't have the time to get to it ASAP, put some HDEO oil in (a 15w/40) and get it fixed. Good luck!

 

[Spyder7]

Originally Posted By: exranger06
Originally Posted By: WhatMeOil


From what I have gathered on this board, the leak(s) was(were) already there but the heavier oil was gunked up enough not to drip.

My questions are:
1) Did I do the right thing switching over to synthetic or have I opened a big can of worms?

There's no reason to be scared of synthetics. Aside from loosening gunk and revealing leaks, it's not gonna do anything bad to your engine.

2) If I switch back to standard oil with the leaking stop?

Probably not.

3) Should I just change the necessary gaskets and keep the synthetic?

Yes, change the gaskets, and then use whatever oil you want, conventional or synthetic. Either way, it won't leak any more because you replaced the gaskets. Remember, the syntehtic didn't really cause the leak, it just made an already bad gasket more apparent. So, replace the gaskets and you'll be good to go.

4) Will the synthetic cause any other internal issues?
No, absolutely not.


+1. I wouldn't put off fixing the leak very long and would monitor the oil level frequently until it is fixed. It may be just a drip on the pavement now, but when it gets nice and hot while you are driving (and thins to operating temp) it'll be flowing freely from the source. And continue to leak until it cools and thickens. Rinse and repeat.

If you can't do the gaskets soon, dump the syn and refill with high mileage and continue to monitor it. If it stops you have two options: fix it and use syn again, or leave it alone and continue to use HM oil.

-Spyder

 

[hpichris]

Honestly, you haven't opened a can of worms.

 

[CharlieJ]

I would have stuck with a 30w HDEO in that old car.

 

[hpichris]

lol

 

[crazyoildude]

Hello and welcome to the board this is the only place to be when it comes to engine oil... Now to help you keep your 455 running great Do yourself a favor get the syn out and use 10w30 high mileage and a new filter do 2 oil changes... The sooner the better What is the temperature where you live?
I own an engine shop and we see a lot of engines that the person loved to death.
That car yoiu purchased is a great car if maintained...How do you know ift only has 60,000 ? Is the brake pedal worn? sometimes on those cars you cant tell if they have 60,000 or 160,000

Only use motor oil in that engine the flushes will clean it but you will probably take out the bearings and or clog the screen...It ran since 69 and probably ran good dont do anything to "make it better"
If you do i will say i told you so...

 

[WhatMeOil]

Thanks for the quick replies. I expect I'll be able to change the problem gaskets before winter sets in. If I use the car at all during the cold weather, I would really rather have a lighter weight synthetic.

sciphi - Have you actually heard of an engine with a flat tappet cam failing because of synthetic? I'd prefer to fix the leak and just use the synthetic if it will be okay for the internals.

--
Jack

 

[WhatMeOil]

Thanks for the reply.

Of course you can never be perfectly sure, but I (supposedly) bought the car from the second owner. He was a mechanic by trade and the engine looked fantastic. Car truly looked like a survivor. He got the car back in 1998 and between then and 2002 he replaced all the external bolt-ons (intake manifold, valve covers, fuel pump, water pump, etc.) He got the car for his father, and wanted to make sure it ran well for him.

Everything about the car says it's all original and low mileage. It runs great, pulls excellent vacuum, purrs like a kitten (growls like a cat?) and I love it. I put in the synthetic strictly for the colder weather, and the fact that I do a lot of shorter trips.

I'm going to have to change the oil anyway if the front cover or pan gasket is the problem (I suspect one or both of them) so maybe the HDEO is the right call because of the age?

 

[hate2work]

I hope it's not dripping out the rear main seal, that would not be good.

Can you see where the drip is coming from?

 

[WhatMeOil]

Sorry, the temps in winter can get pretty cold - especially if you drive up in the Tahoe area. Certainly gets below freezing quite a bit at night.

 

[Spyder7]

Does Nevada get as cold as Texas?

Not sure why you guys so far south are so obsessed with the pour point benefits of synthetic.

Closest to Nevada I've been was Northern California in April, and it was as warm there then as most of our better summer days here (I really, really, did not want to come back to the snow still on the ground and bitter North Westerly driven sleet that cuts through you like you're doing laps in the North Atlantic).

Edit: on a more helpful note, Valvoline MaxLife will give you all the cold flow you need while giving this well worn engine the TLC it needs.

-Spyder

 

[WhatMeOil]

It looks like it's the front seal, or maybe the pan. There is some old built-up crud right in that area that I cleaned off. I'll be checking over the next couple of days. Wont' be fun pulling the balancer, but I can't park in the driveway until I can get it stopped!

 

[WhatMeOil]

Yeah, it's the elevation. NorCal has a very mild winter, they don't get snow on the valley floor (well maybe once every 30 years) but Reno is regular winter. It's worse the higher you go, but I certainly think the synthetic would have worked better for winter.

I think I might try the High Mileage or Heavy Duty and go with a 10-40. Seems like it might be a "quick fix" and then I can look into still changing the gaskets.

Thanks again everyone! This board is awesome - so many active users!

 

[spasm3]

I'm not sure you need a synthetic here. Pennzoil high mileage 10w30 is what i would put in it. Perhaps even rotella 15w40 in the summer.

 

[Summerwind]

Oldsmobile Rocket 455......sigh...Last big block that I had, and with many fond memories!!!

My Old Sweetheart would start fine in the cold Wisconsin winters with Dino 10w30 back in the 70's. As you and others have suggested, I would go with a good 10w30 HM dino oil and call it good

 

[crazyoildude]

ok then try 5w30 high mileage i use pennzoil or valvoline hm