76 vette been sitting for over 5 yrs maybe more. Full of oil but very black. Any recommendations for first oil change to clean it? Sea foam? Something else?

 

If it were me, I'd just put a conventional 10w30 in it, drive a couple of hundred miles, and if it looked funky, I'd change it again. There is a recent thread talking about sea foam in the crankcase, most said they had never heard of it going in the oil. I don't feel comfortable diluting my motor oil.

 

Should i not be worried about dust and gunk in it??

 

Unless you are buying non detergent oil last available in the 1950s, all modern motor oil has detergents in it to "clean" the engine. Change the oil and filter like mortgageguy suggested. Last time a shade tree mechanic friend "cleaned" his engine with some redneck concoction, he spun three main bearings due to poor lubrication and had to rebuild the engine.

 

Fresh oil will pick up the remaining contaminates. If the past maintenance is unknown you can pull a valve cover to look for sludge.

 

Seafoam is perfectly safe to clean a dirty engine.. Its urban myths like that spinning bearings that confuse the uninformed.. It has been around since 1930 ,cleaning engines and fuel systems.. was first designed for Marine engines that see limited use and sludge build up ..made completely of petroleum products, 6 oz, as recommended, in a 5 qt system is no more dilution than putting a teaspoon of hot water in your ice tea. Use it or not, your choice but ignore the erroneous engine destruction claims ..its simply not fact

 

Would not use any special cleanser. Just get some oil with high zddp for the flat tappet cam that's in it.

 

Not one automotive manufacturer, in the world, has approved sea foam to be used in their fuel or lubrication system. GM has approved the use of Techron in their fuel system only. It is covered in a TSB concerning their DI engines with deposit build up on their valves.
I just don't think the OP needs to overthink or complicate the process. For just a little over $20, he can run it a couple of hundred miles and then evaluate. I like to keep it simple. At least see what happens before dumping chemicals in the oil.

 

I don t really care if he uses it or not, ITS HIS CAR! just dispelling myths like " Seafoam will cause your mains to spin.". its simply not true.. its not "a redneck concoction" as someone posted..BTW, No manufacturer approves a bigger Comp Cam in your engine either, but that doesn t cause damage either.. we have used it in marine engines, gas and diesel for decades.. it works.. Go to the C5 section here and ask how many of us have fixed a non-working fuel gauge by just pouring a can in the tank..

 

I would change the oil using a good 10w-30 as mentioned and a Napa Gold 1069 oil filter. A big quality filter is a good idea. I'd check the oil often and probably change again at 500 miles or so.

The Penzoil Ultra has a lot of extra detergent for cleaning out deposits. It is a synthetic. I would probably run conventional for a few oil changes first. I have zero fear of using synthetic in a high mileage motor having started using it in a 165,000 mile 305 v8 and running the engine to almost 400,000 miles on the high mileage synthetic.

I've heard of using Seafoam in the crankcase but haven't done it before.

 

Change the oil and filter. The oil filter will pull out any 'dust & gunk' that may have formed in the pan over time. The oil is pressurized by the pump, then filtered BEFORE circulating through the engine.

Also change-out any fuel filter (in-line or in-carb) and either drain any [condensation] water out of the fuel tank or put "de-icer" treatment in the tank [it's just alcohol that will absorb the water and mix with the fuel].

After charging the battery, spin it over a few times to make sure it turns over freely; then pump fuel and try to start it. DON"T PUMP THE CARB FIRST!! The internals on the carb will be completely dry and the fuel pump needs to fill the carb before you actuate the accelerator pump...or you might tear or knock the pump shaft seal off the rod. Once it is filled with fuel (10 seconds, maybe), you should be OK to work the carb.

Don't run starter over about 10-15 seconds at a time. Then let set for a minute or two to let the starter cool back down. You can overheat/burn-out a starter that is forced to crank constantly.

If the engine won't fire after a reasonably good effort, you probably should change points, condenser and rotor (if a points car). Condenser can go bad just sitting for that long; points and rotor contacts can corrode. Pulling plugs would be a PITA to do and would be the LAST on my list to get a 'storage' engine started.

 

Go back and read post #4, nobody said "Seafoam is a redneck concoction" that's just the way you took it. So you fixed fuel gages by pouring it in the tank, that's still not the crankcase.

 

now go back and read my post... .............." we have used it in marine engines, gas and diesel for decades.. it works.. " ...............that's in the crankcase

 

I did read it. Only now do you state crankcase. Thanks for the clarification, lol!

 

simple facts...".Any petroleum oil or fuel (petroleum hydrocarbon molecules) or oil w/detergents CANNOT dissolve its own petroleum residues. You cannot clean oil paint from your hands with oil paint, or water, or detergents. You use a higher-refined oil solvent.

Sea Foam is 100% organic crude-derived, highly refined oil with greater solvency abilities than gas, diesel, motor oil, transmission and power steering fluid. When added to any, it’s oil that dissolves all types of petroleum residues + lubricates. In terms of lubrication, Sea Foam’s majority ingredient will not burn under extreme chamber heat. What does that tell you about its harmlessness when added to crankcase oil.?... " I rest my case... use it ,don t use it, I don t care ,but to pretend it causes engine damage is factually wrong.. and to spread misinformation is dishonest

 

Hello? Nobody dissed your beloved Seafoam. You are the one who equated "redneck concoction" with Seafoam, lol!

 

Since I made the redneck comment, let me clarify. In 1999, while living in Vale, NC, I sold my 87 Chevy truck with a completely rebuilt 454 to my farrier, Chris Merritt. It ran perfectly and I personally bought all of the parts and did all the engine work except pressing in the cam bearings and boring the cylinders. The block was hot tanked to remove all crap from the metal surfaces. There were about 5K miles on the rebuild when I sold it. Several weeks after I sold it, Chris showed up to shoe my horses and began complaining that there was a low speed miss in the engine and his buddy, who did car repairs at his house as a part time business, was trying to find the problem. About two weeks later Chris called and said the engine had "blown up" and he had his buddy replace the 454 with a used 350. When I asked exactly what happened he said his "mechanic" buddy (this would be the redneck) claimed the low speed miss was caused by sludge in the engine and had put an "oil cleaner" in the oil. A couple days later while Chris was driving the truck, the engine began to clatter, bang, seized up and stopped. I wanted the four-bolt 454 engine, so I bought it back for $200. When I examined it, I found a cracked distributor cap (probably the cause of the engine miss) and upon tearing the engine down found three spun main bearings and almost all of the rod journals on the crank were blue from overheating. I don't know for certain the brand name of the "oil cleaner", but the results of cleaning an engine that did not need cleaning in this case caused engine failure. I'm old enough to remember what sludge in an engine using non-detergent oil looked like back in the early 1950s, but modern motor oil already has detergents in it to prevent sludge buildup. Ron Arndt

 

Hey Hawg, you're new to this forum, we kind of let this one get away from us. I hope we didn't come across like some little boys argueing over who's dog is better. We actually support each other and this wonderful Corvette hobby. No one in this thread would advise you to do anything that would hurt your car. So, hang with us, and let us know how your project is going. By-the-way, how's your project going?

 

Good answer.

 

I did a search on C5 tech section. I found one guy that said that seafoam fixed a gas gage but had also used Techron, three that said it didn't work and used seafoam as well as techron, and a few others that said to use Techron. Does that mean it'll de-sludge his motor? He really should pull a valvecover before jumping into additives, he could probably get a good enough look into the oil filler cap to see, this may not even be an issue.