Oil for my 88 f150.

mpack88

mpack88

Joined
Aug 2, 2018
Messages
948
Location
South Carolina
Right now I have a stash of RGT 5w30 but no vehicle that recommends that. I know 5w30 can be used where 10w30 was recommended. My 88f150 is due for a change and wondering if yall think it will do fine. She's probably got loads of miles and uses oil. She's a flat tappet aswell. Right now I got 15w40 trying to slow its consumption but I have notice it took a hit on fuel milage. Engine is a 5.0L by the way.
 
The manual for my 87 F150 states 5w-30 can be used for temps up to 60 degrees. If you are consuming oil, I would use 10w-40 year round for your area and just keep it topped off.
 
Last edited:
mpack88 said:
Right now I have a stash of RGT 5w30 but no vehicle that recommends that. I know 5w30 can be used where 10w30 was recommended. My 88f150 is due for a change and wondering if yall think it will do fine. She's probably got loads of miles and uses oil. She's a flat tappet aswell. Right now I got 15w40 trying to slow its consumption but I have notice it took a hit on fuel milage. Engine is a 5.0L by the way.
Click to expand...

How much consumption are you experiencing? 5w-30 is fine.
 
One of my ex's step dad's had a 90 that burned a qt every 1-2k miles and eventually blew a hole in a piston. Lots of them were replaced under warranty for oil usage late 80s to 90s according to my friend that worked at the dealer those years.

I would use whatever you have and change reasonably early.
 
I'm curious to try 20w 50. But the engine doesn't leak at all in fact it runs fine. It does not smoke but the oil go somewhere. The truck is not worth a new engine but I don't think it needs one either.
 
mpack88 said:
I'm curious to try 20w 50. But the engine doesn't leak at all in fact it runs fine. It does not smoke but the oil go somewhere. The truck is not worth a new engine but I don't think it needs one either.
Click to expand...
Blowby from the rings most likely. It usually comes from the crankcase breather and not exhaust on those engines. When they fail catastrophically it will start blowing oil out the breather.

Not that it's going to happen, it could burn oil for years without issue.
 
350Rocket said:
Blowby from the rings most likely. It usually comes from the crankcase breather and not exhaust on those engines. When they fail catastrophically it will start blowing oil out the breather.

Not that it's going to happen, it could burn oil for years without issue.
Click to expand...
I'll check it when I get some time.
 
It could be some or all of these items: a bad pcv valve, worn rings, worn valve guides, bad stem seals, or the rings are coked up. I would try something like Rislone, Kreen, or MMO to clean things up. It might also be worth pulling a valve cover and having a look at the valve stem seals. Odds are they could be rock hard, and some broke like glass causing your oil use. A 0W40, 5W40 or even 10W40 will be fine in it. In the dead of winter I'd use a 0w or 5w40.
 
Bet the manual calls for 10W-40. I would run something ending in 40 or 50, depending on weather. Check the PCV system as stated. Maybe put something in to try to clean rings.
 
350Rocket said:
Blowby from the rings most likely. It usually comes from the crankcase breather and not exhaust on those engines. When they fail catastrophically it will start blowing oil out the breather.

Not that it's going to happen, it could burn oil for years without issue.
Click to expand...
Just pull out the PCV and breather, smoking like a tea kettle with some pressure out of those points in the valve cover indicate blow by.
 
Oil consumption through the PCV system was incredibly common on the Windsor. In the cars it was often a plugged PCV screen, which is buried below the grommet for the PCV valve in the back of the intake manifold.

I did a 302HO swap on one years ago, the pictures were posted on here.

On the PCV on the truck, I believe it is on the valve cover and there was a relocation of where it met the intake at some point, because it was apparently dumping into #8:

Relocated PCV hose 1993 F150 *a must do project?* - F150online Forums

Pre-1997 Models - Relocated PCV hose 1993 F150 *a must do project?* - Hi guys, I think i remember reading that, up to a certain year, there was a TSB or something saying to relocate your PCV hose because it was causing issues with #8 cylinder/piston. I *think* the fix for this was to remove the...
www.f150online.com

If you haven't replaced the valve in a while, that project may be worth embarking upon.
 
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