Yet ANOTHER oil leak!

[Krusty]

Yup... I'm back... with ANOTHER oil leak on the 2001 C5
After a few months off the road whilst the weather is bad and I've been messing around with my other cars and motorcycles, I've come to my C5 to put it back on the road for April 1st only to find my entire sump is soaked with engine oil
I noticed it around 2 weeks ago when I had my car elevated off the ground whilst I was cleaning my brakes, also checking, cleaning, regreasing and retorque'ing various components (steering and suspension related). I glanced under the car and noticed my entire oil pan was covered in engine oil!
The car hasn't been off my driveway for over 4 months and I know it was dry when I parked it up. So I cleaned all the oil off the lower pan (I believe its called a bat wing?), I came to it tonight just to start the car up as I have been doing every 2 weeks to keep the motor good and battery charged... before starting I checked and noticed its completely wet again! (even though the car has not moved anywhere).
A quick look with my inspection camera behind the alternator, it looks like the upper oil pan could be the issue. I just want to know if it really is an involved job as I've read online? if it is then I'm going to have to take it to a shop for it to be done.
I'm so annoyed at the car! it seems every time I come to it, it has another leak! only 65.8k miles and I've already replaced the valve cover gaskets, the oil pressure switch, the valley cover gasket, the front timing cover and gasket including main seal whilst it was off and the PCV piping. ALL of which have been the cause of oil leaks in the last 2 years of ownership.
I'm starting to debate selling the car again, its becoming a 'never meet your childhood hero' scenario! not once have I came to this car and it hasn't give me an issue of some description

Any insight on the job and if it can be done at home, would be a great help. Cheers

 

[teamzr1]

Maybe best to wash engine down, add oil with some oil UV dye in it
Kits are sold that come with either a black or blue light that shines where the dye has leaked
so could check and then look for highest part where dye came out and ran downward

https://www.amazon.com/s?k=engine+oil+dye&crid=OSVOHJOJ57JS&sprefix=engine+oil+%2Caps%2C195&ref=nb_sb_ss_ab-sx-reranking-v3-desktop_1_11

 

[Krusty]

I bit the bullet today and just called Parts USA to book the car in for repair.
Unfortunately, lack of workshop ramp and working all the time (motorcycle trade and it's approaching biking season so really busy!). It's easier for me to just get it done by the guys that have helped me with a few of my leaks in the past already
I'll keep you all updated on what the issue is

 

[Mr. Cricket]

I bit the bullet today and just called Parts USA to book the car in for repair.
Unfortunately, lack of workshop ramp and working all the time (motorcycle trade and it's approaching biking season so really busy!). It's easier for me to just get it done by the guys that have helped me with a few of my leaks in the past already
I'll keep you all updated on what the issue is

Don't forget to claim your club discount which there is well worth having and cheer up

 

[C5Steve]

Just remember it's not leaking oil, it's sweating power

I've got a similar leak in the same area, very very small though and I will get around to it but it's not bothered me. I remember when I took my car to Claremount for something just after I got it and mentioned it to Tom and he said "A Corvette with an oil leak, now that's a surprise!". His sarcasm put my mind at rest.

Glad you're getting it sorted

 

[Ian at Forfar]

Hi ,
think you have been very unlucky had mine 21 years no leaks , two of my friends have C5s again no problems .
well worth getting to the bottom of the problem and then you can enjoy .
Good luck

 

[teamzr1]

Having worked on many C5s and knowing many others owning them, there has never been leaking engine oil issues
including my 1999 C5
In fact, same as to newer gen Corvettes

I am wondering if the type of oil used is the cause, as an example when I had C4 ZR-1s and did a lot of racing with them
the owner of Redline oil came to me and begged me to replace the Mobil-I oil with his and assured me there would be no issues
and would not void GM warranty

Well that crap caused all types of engine leaks including the oil would float up the valve cover bolts and leak out
and GM voided the warranty when seeing that red colored engine oil
Also, their tranny fluid caused synchro failures which GM also voided warranty and cost me over $5,000 to replace

I had a testlab when at GM in Warren, Mi and Mobil-I had a lab next to mine
They non-stop test their products to assure there are no issues to gaskets, O-rings, piston rings, etc

So there is a lot more into fluids and oils makeups to assure functional to internals of engines, tranny, rear ends

 

[Krusty]

Thanks for all the support everyone, the lot of you are good eggs! I do think I may of just be unlucky... but hopefully this will be the end of it once and for all!
The good fellows at Parts USA remember me well and have reminded me about my discount
As for the oil, I have been using MANNOL Energy Formula JP Synthetic Engine Oil. SAE 5W-30; API SN; ILSAC GF-5 which was recommended to me through this group

 

[teamzr1]

Myself would not use 5w30 as the viscosity is too light and in hotter engine temps, RPMs or loads becomes blow by
Might get a bit higher MPG, but that is about it

I use at least 10w30 or as Mobil I engineers told many years ago is to mix viscosity as to weather, street or track
I use as GM recommends for track, like a 20w40 or mix 50/50 of 5w30 with 15w40

 

[Krusty]

Here in the UK, we have quite a wet and cold climate throughout the year with highest temps of around mid 30's (Celsius) in the height of summer (and that's if we're lucky!).
We might occasionally get hotter temps here and there for a few days but certainly not a week! I don't tend to drive the car in extreme temperatures (for the UK at least) and the car doesn't get a hard life at all with me. I only tend cruise around and enjoy the sights in the car, with the occasional boot down along an open stretch of road where visibility is clear and obvious of no Police or other hazards.
Baffles me why I would of been recommended this specific oil when I first joined, if it isn't right for this car in UK climates More annoying that I currently have over 25ltrs of it and oil filters bought in advance for future servicing

 

[teamzr1]

GM suggests 5w30, the thinnest viscosity, as it would get just a bit better gas mileage
Being your hottest weather and not much of it is about 90 F deg, and you're not using high RPMs above let's say 4,000 RPMs
what you have would be OK
GM now suggests for newer vehicles an even thinner 0w40 but says for hot weather and/or racing to switch to a 5w50
and switch back to 0w40 for street use
So clearly they even know the thin viscosity is for fuel mileage but knows for other conditions it is too light

As the engine gets older and lots of miles on it than of course there is wear on the piston rings, where 5w30 than can slip past the rings and
oil burning loss is seen and have to add oil

Where like using a 10w30 being thicker viscosity may not get past the rings

Being my C5 is not a daily driver, can care less about a bit better MPG and always buzzing rev limiter
set at 6,800 RPMs on street, I rather use the 10w30 viscosity for street only

So for your drivestyle what you have is fine to use up
If hotter weather or getting on the engine load/RPMs you could mix some 10w40 with the 5w30 as long as same brand and type
like if using synthetic than both should also be

If you notice, the newest Mobil I supercar version is 0w40, but no way I would use that Viscosity Grade
Imagine the C8 Z06 FPC engine with 32 valves and 4 overhead CAMS
buzzing the 7,200 RPM rev limiter in hot or race conditions with 0w40 becomes blow by

 

[Ian at Forfar]

Your 5w 30 is just fine , thats what I used for 21 years

 

[Krusty]

I have to say that I have never lost any oil when checking the level on the dipstick, despite having oil leaks that I've been continuously chasing!
Because I have always had some sort of leak, I have religiously checked my oil level before and after every single drive, but never lost a noticeable amount... I guess I've just been sorting them straight away as they've become apparent, rather than leaving them to develop