1995 Chevy 350, P30 - Do I want to use synthetic?

Status
Not open for further replies.
Joined
Dec 22, 2017
Messages
1
Location
Florida-Panhandle
Anyone have a P30 out there? I just got a 1995 P30 Step Van. I'm converting to an ice cream truck. The truck is powered by a 350 Chevy engine. The truck has 140,000 on it.

I read posts here about using oil and decided that my first oil change would be a Castrol GTX High Mileage 5/30 which I did. I'd like to move to synthetic, but I've read about potential leaky seals with the 350 Chevy engine. The truck is new to me. I just installed new spark plugs. Absolutely no oil around the plugs. Does this necessarily mean that seals are good or only the rings? Is it worth the trouble to convert to synthetic? I do my own oil changes on my vehicles, my other being a sedan. I like that I can find synthetic oil with filter for $23-25 and not change oil for 6,000 miles vs 3,000 with conventional oil. Keep in mind this vehicle, as an ice cream truck, will idle a lot or crawl through neighborhoods.

Opinions, please.
 
M1 HM in either the 10W-30 or 10W-40 grade.
Hit some AZs in the next few days and you may be able to pick up the ten forty for two bucks a quart.
 
If you use synthetic, the Valvoline Synthetic with MaxLife Technology is a good choice-full syn with seal swellers in it. M1 HM would be my second choice. I had a '94 TBI 350 Suburban with over 200K, it actually did the best on 20W50 Maxlife syn blend-but the 20W50 might be a little tougher to find these days.
 
The old 350 motors aren't picky about oil. You could run a 10w30 or 10w40 easily. Most of the synthetics on the market today won't cause leaks that I have seen. A good oil that is semi synthetic in a 10w30 weight is Rotella T5. Would be a good choice for your application. It's cheap and you can find it anywhere.
 
Originally Posted By: MParr
Move up to Castrol GTX High Mileage 10W30 or any other high mileage brand of 10W30.



I agree with this. A good Semi-syn High mileage oil like Castrol or Valvoline Maxlife would get my vote.

And 10w30 is a good choice for a older motor and/or warm locations like FL.
 
"Converting to synthetic" is an overstatement. Many owners who don't have a clue - and even some that do - flop back and forth without a problem. I, however, believe in finding an oil that I have peace of mind in for the vehicle in question, and sticking with it.

I'd use a 10w30 or 5w40 in your application. Start with a high mileage syn or syn blend in 10w30 (my go-to would be Maxlife) and if it doesn't leak or use much of it, stick with it. My dad has a '97 Suburban with a 350 - several months ago it had 430K on it and still runs like it's got less than 100K on it. He got it at 170K, 11 years ago, and has used Maxlife 10w30 or '40 in it ever since. The 350 is a good power plant.

5w40's don't come in as many (if any?) varieties of a high mileage formulation, but if it doesn't leak much a HM oil isn't a necessity. Outside the realm of HM oils, Rotella T5 is available in 10w30 and T6 in 5w40. I'm also partial to Schaeffer's products and use their 10w30 ('85 GMC 454) and 5w40 ('82 Benz diesel) - I believe Schaeffer is a very resilient oil and worth the extra money.
 
Last edited:
at least 10w30 for idling and something for seal maintenance. Thicker oil with the numbers as close as possible was the old mantra. Just like necktie width, oil fashions change. You really can't make a bad choice in oil these days. PS All my ties are wide. Merry Xmas
grin2.gif
 
On a new to me 350 in Florida I'd probably go with a cheap conventional 10W30, or any xW30, and run it for a bit. And see what it does. I'd hate to pour in Royal Purple only to find it drinks oil like a sailor! In a big truck I'd think xW30 would be fine around town, and xW40 if sustained highway.

Lots of low speed driving, kinda points me to think of shorter OCI's. Many of these engines went to huge miles on 3k OCI's and conventional. I'm not sure I'd over-think it.
 
Don't waste any money on synthetic.

Use a good 10/30 HM and forget it.

That engine is not going to die of a lube related issue, or even suffer by one.

I would do one UOA to find out if your are suffering from high fuel dilution with it being a TBI engine. If you have FD issues, you're going to want to keep that OCI shorter.

I would get new fuel injectors on that engine one way or another. When they get old and less efficient, they can cause serious FD issues.
 
10w-40HM all day long. Walmart Supertech is cheap and available. In your climate and with all the idling I might even go 15w-40. Your motor will thank you. Some fresh ATF won't hurt either. Walmart ATF (Dex3/Mercon spec) will work great here too.
 
The savings of Supertech conventional and ATF over the same stuff in Valvoline Maxlife flavors is less than $5 a gallon. If nothing else I count the peace of mind worth more than that, and I believe VML is a better product.

Also, if it'll fit (good chance it will) a Wix 51794 is a good upgraded oil filter that'll give you over a quart more oil capacity which has multiple benefits.
 
Last edited:
I have nearly 280,000 miles on my K3500 (454) and it's seen the cheapest 15W-40 (tractor, diesel, etc.) oil money can buy all its life.

Harvest King 15W-40 is $12 for a 2 GALLON jug.

You can't go wrong with 15W-40 HDEO in this engine/truck.
 
Originally Posted By: Alex_V

Also, if it'll fit (good chance it will) a Wix 51794 is a good upgraded oil filter that'll give you over a quart more oil capacity which has multiple benefits.


Do not use this oil filter just because it's huge. It's efficiency numbers stink.

A Fram XG5A will filter much finer (as well Dolaldson, AmsOil, Royal Purple) oil filters.
 
No synthetic - use HM 10W-30 or 40. Or some HDEO as suggested by Linctex above. just keep it topped off and change it every now and then and you'll be fine. Those old 350s are really hard to kill.
 
Status
Not open for further replies.
Back
Top