305 sitting for years, low coolant and water in oil

[chillman88]

Hey folks,

Short version is this has been sitting for over a decade and there's water in the oil. My first thought is Intake manifold but how should I diagnose properly? Doesn't seem prudent to run it if it's ingesting water but would a compression test be a good indicator on an engine that has sat so long? Coolant is low, radiator is about half full.

Long/extended version with details below....

Technically this is in a car but I wasn't sure where else to ask and the engines are the same so I'm hoping it's ok. 87 Caprice, 305 with the Computer controlled quadrajet.

This car has been sitting since at LEAST 2009. I was told it has been sitting for 19 years but the old man passed in '09 and the last reg expired in 2010. Vehicle has 74k original miles, one owner.

Initial inspection oil looked very clean but overfull. Fired right up with some gas in the carb. Spit and sputtered for a couple seconds then purred like ot was just parked the day before.

I'm going to change the oil and run it for a short time to purge any water from the oil galleys.

Should I just pull the intake and check the gaskets? Fill the radiator and let it warm up while looking for bubbles?

Thanks in advance,
--Chris

[Dead Parrot]

Test the coolant for freeze point. Possible it froze at some point. Was it stored in a heated or outside place?

How much water in the oil? Was it coolant or just water? Wondering if you have 15 years of condensate accumulation. How overfull was the oil? A 1/2 full radiator usually needs about a gallon of coolant to fill.

A half full radiator might be due to a bad water pump seal and years of slow leakage. Or the radiator itself rotting out. Same for heater core.

Since you have already started and ran it, doesn't sound like there was any water in the cylinders. I would change the oil, add water, add fresh gas and start and run it. Leave the radiator cap off. See what happens.

After the run, check the fresh oil for both water and gas smell(leaking fuel pump).

[chillman88]

Originally Posted by Dead Parrot

Test the coolant for freeze point. Possible it froze at some point. Was it stored in a heated or outside place?

How much water in the oil? Was it coolant or just water? Wondering if you have 15 years of condensate accumulation. How overfull was the oil? A 1/2 full radiator usually needs about a gallon of coolant to fill.

I don't really think it froze but that's a good idea to check. It came from Wisconsin and was in NY so hopefully the mix ratio was correct for the climate. I'd be more worried if it came up from down south. I haven't drained the oil yet but judging by the dipstick I'd guess about a gallon. Just got it home last night so I'll be grabbing some oil after work and draining it and I can tell better then.

Originally Posted by Dead Parrot

A half full radiator might be due to a bad water pump seal and years of slow leakage. Or the radiator itself rotting out. Same for heater core.

Since you have already started and ran it, doesn't sound like there was any water in the cylinders. I would change the oil, add water, add fresh gas and start and run it. Leave the radiator cap off. See what happens.

After the run, check the fresh oil for both water and gas smell(leaking fuel pump).

That sounds like a good idea thanks. I'm very good at jumping the gun and trying to avoid that.

I will drain the oil and leave the plug out while filling the coolant just to catch it if it is leaking internally.

I'm leaning towards changing the fuel pump before putting it back on the road for peace of mind. I wouldn't be surprised if that's the original pump and if the diaphragm isn't leaking now a few hours of running after sitting so long isn't going to be well received I'm sure!

I will update later thank you!

[Slammed84]

This reminds me of a Vice Grip Garage video.

[Dead Parrot]

If you have time, after draining the oil and filling the radiator, let it sit for several hours or even overnight with the oil plug out. If there is a slow coolant leak, you should know by next morning.

Of course, you may know after a bunch of coolant comes out the oil drain hole.

[chillman88]

Originally Posted by Slammed84

This reminds me of a Vice Grip Garage video.

The car was less than a mile from my house. If it had brakes I probably would have tried to drive it home. One or more of the brake lines are blown which is probably a good thing because it stopped me from being pig-headed and ruining the motor.....

[chillman88]

I don't know if the photo link will work or not but the oil cap tells me this might have been going on longer than I thought.

https://photos.app.goo.gl/iqdezGYspvNwAjAz5

I woke up way too early this morning so I went out a drained the oil (pouring rain all day yesterday). I really didn't like the oily sludge in the bottom of the pan... I decided to flush it a little bit with some diesel and that's when I saw the condition of the oil cap.

I put the drain plug back in and it's sitting with maybe a gallon of diesel in the crankcase. I'll let that sit at least until after work today and then proceed from there.

I'm going to stay optimistic because it ran so well when I test fired it.

I'll add coolant after I drain the diesel and when I figure that out (barring anything major) it'll be a couple short oil changes to clean everything up.

I'm hoping I don't have to but really worst case I have a stock 350 I pulled from a C20 I can swap in. Even the oil pan is clean and rust free on this car. Unreal.

[chillman88]

Originally Posted by Dead Parrot

Test the coolant for freeze point. Possible it froze at some point.

A 1/2 full radiator usually needs about a gallon of coolant to fill.

If the picture comes through it's the coolant tester. I'm honestly wondering if the water just evaporated over time somehow. Doesn't make sense being a closed system but it looks like straight antifreeze and reads as straight antifreeze too.

https://photos.app.goo.gl/YD4q5Zk3nMvmy4rr5

I added roughly a gallon of fresh premix.

Originally Posted by Dead Parrot

If you have time, after draining the oil and filling the radiator, let it sit for several hours or even overnight with the oil plug out. If there is a slow coolant leak, you should know by next morning.

Of course, you may know after a bunch of coolant comes out the oil drain hole.

Drain plug is out and no coolant coming out yet. It's sitting with the radiator cap on at an angle so it's fully vented to atmosphere.

Maybe I'll get lucky and it's just fine? Would be amazing.

Would you add anything to the initial oil change? A pint of diesel or something? Or just run it until it's warmed up and drain it hot? (assuming there aren't any fuel issues, last time I ran it might have just been fresh gas in the carb running and nothing from the tank).

I was planning on adding a pint of sta-bil and 5 gallons of ethanol free high test. Tank feels empty tapping on the bottom.