Synthetic in an 86 302 w/ 120k miles?

[Jaymus]

Well, guys, I guess a lot of people are tired of hearing posts like this. But, I love to have second (and third and fourth) opinions.

I have an '86 F-150 with a 302. It has 120k miles on it. Conventional all its life. I believe it had Kendall in it until I got it with 109k miles on it. Had Castrol GTX every 3k or less on it since I've had it.

BUT, I'm wanting to use Castrol Syntec 0w30 in it, now. I like the viscosity of it. Almost a 40, but still a 30. I like the oil pressure that would give me when fully warmed. It will be good year round. 0W for winter and a good viscosity for when its warmed up. I also like Syntec from experiencing it in my lawnmower. It has 0 consumption with it, now. It used to use conventional oil, and supertech synthetic. But, none at all, now.

ANYWAYS, can't compare a 4 year old lawnmower to my 22 year old truck engine.

GC has more zinc than normal GTX, too.

So, tell me what I need to know about seals possibly leaking later on. It has NO leaks right now. It smokes NONE at all. Oil consumption is extremely small. Well, the only 'leak' on it is from the drain plug... but I need a better gasket for my plug and it should be fixed. I know it will leak worse overnight with a 0w30 in it, compared to my current 10w30 I use in it.

I would run it 6-7k miles before changing the oil. Just wanting to see other thoughts on it.

 

[OVERKILL]

You'll be fine.

302's are known for the rear mains leaking, and the valve covers, as well as the intake-to-block seals (cork) weeping.

Keep the PCV working well and you should be fine. The typical cause of the end-seal leaks is crankcase pressure.

When the valve covers start to leak (not if), replace them with the gaskets for the Explorer. They are steel-impregnated rubber and will never leak. Same goes for the intake seals, which are also rubber for the Explorer.

Rear-main is a PITA though.

 

[Jaymus]

When do most 302's rear mains start to leak? My valve cover gaskets aren't leaking, yet. At least they won't be a PITA to replace. Thanks for the explorer gaskets tip!

 

[OVERKILL]

Originally Posted By: Jaymus
When do most 302's rear mains start to leak? My valve cover gaskets aren't leaking, yet. At least they won't be a PITA to replace. Thanks for the explorer gaskets tip!


5spd or auto?

The one on my Mustang went at around 250,000Km, the one on my Lincoln started to weep (a LOT less than the 'stang) at around 290,000Km.

 

[Drivebelt]

I think you're asking for a seal leak by going with a synthetic that uses PAO like Castro Syntec 0w30 in an older car. Synthetic's that use PAO's can cause leaks on seals on older cars -- and probably even more so if these cars are prone to having seals leak. It may not cause problems -- but I think there is a good chance it will.

I would use a 10w30 HDEO (Group II) or some Group III synthetic if you want something a little better than conventional oils.

 

[mechtech2]

I noticed that you related how well the engine was doing [really well], and that you therefore want to change the oil type and brand.
That's one way to do it!

 

[OVERKILL]

Originally Posted By: mechtech2
I noticed that you related how well the engine was doing [really well], and that you therefore want to change the oil type and brand.
That's one way to do it!


It's a 302. I've used everything from 0w20 to 5w50 in mine. Current fill on the Townie is M1 TDT 5w40, which it seems to like. It also liked the 0w40.

The mileage for each are in my sig. They aren't sensitive engines.

 

[battyice]

x2 on the valve covers, 2 out of 3 of my 302 powered vehicles needed them around 100k. My 88 grand marquis and 89 mustang both needed gaskets when I bought the vehicles. I used the felpro gaskets with the steel inserts, neither of them leaked a drop after that. My 88 bronco never leaked a drop of oil from anything, even when it had 165k on it. I ran synthetic oil in all three and never had any issues with the rear main seal leaking.

I tried various viscosities in each vehicle, they all did really well on rotella synthetic 5w40.

 

[TeeDub]

I don't see a problem with this, but I'd do several things first:

1) Replace the valve cover and oil pan gaskets before doing anything else.

2) Run a bottle of ARX in the motor for 3000 miles to clean out deposits (with a new oil filter). Forget about the "rinse" phase, it's really not needed based on personal experience with ARX.

3) Install the 0w-30....

 

[Gary Allan]

Quote:
Forget about the "rinse" phase, it's really not needed based on personal experience with ARX.


I would say that this is "more true" in terms of coked rings and places with forced circulation (like turbos). Deposits that are in the form of surface formations take a bit longer. Now you'll be doing rinsing with the next oil change ..but if you're liberating substantial formations.. shorter OCI's would probably be in order. This sensibly infers that a cheaper oil (suitable for going the distance in the application) would be used.

 

[OVERKILL]

Originally Posted By: battyice
x2 on the valve covers, 2 out of 3 of my 302 powered vehicles needed them around 100k. My 88 grand marquis and 89 mustang both needed gaskets when I bought the vehicles. I used the felpro gaskets with the steel inserts, neither of them leaked a drop after that. My 88 bronco never leaked a drop of oil from anything, even when it had 165k on it. I ran synthetic oil in all three and never had any issues with the rear main seal leaking.

I tried various viscosities in each vehicle, they all did really well on rotella synthetic 5w40.


Yup, the Felpro ones are the same gasket. Sometimes the Explorer ones are cheaper (and readily available at a dealership), which is why I suggested them.

They do seem to really like a 5w40 HDEO from what I'm seeing with the Lincoln.

 

[bobfather99]

I would say it would depend on if youre still going to do the 3000 mile runs with the oil. If so, Id just stay with the GTX.

I had an 83 F150 with the carbed 302 Keep the PCV valve and lines clean(I had to use a screwdriver to clean mine) and replace the valve cover gaskets/oil pan gasket(if you need to)

I never did replace my rear main(it seeped a little, but not enough to justify replacing) I just did the maintenance and changed/topped off the oil. Still ran when it was sold(it was JUNKYARD rusty) but I drove it everyday.