The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support Fuel Injector Clinic
Please Support Fuel Injector Clinic

Best oil for a worn out 4g63t

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Nathan Jorgenson

Probationary Member
12
2
Jul 14, 2017
Sundre, AB_Canada
Just wondering what would be the best oil choice for a 1990 Plymouth Laser RS?
I do live in Canada and I does get very cold and the car will be winter driven. The car does have a block heater and it will be used.

I imagine in the south guys just use 10w30. I run Shell Rotella full synthetic 5w40 In my Dodge Dakota would that work for the Laser?

The Car does burn a little oil has anyone tried a b/g hot oil change and seen any improvements? If anyone wants to see for the fun of it I'll post the compression before and after the hot oil change on here.
 
5w for your winter.
40 to help compensate for the wear level of your old engine.
So, 5w-40 is good.
My overall fave 5w-40 is Castrol Edge (full synthetic) A3/B4 "Euro". That's how it's labeled in the US anyway.
It has the ACEA A3/B4 rating which is the European "right stuff" rating for high performance gasoline engines. That guarantees an HTHS viscosity of at least 3.5 which is good. (5w-30 or even 10w-30 oils will usually have a lower HTHS viscosity than that unless you are talking exotic oils like Red Line).
You can buy it in a 5 quart jug which saves you a lot of money (it's a lot cheaper per quart).
Your Rotella T6 is going to have an ACEA rating of E9 which is a diesel spec. For gasoline engines the A3/B4 is a better spec for anti-wear. Diesel spec oils these days have to be ok for particulate filters. The A3/B4 spec doesn't have that requirement holding it down.
I've been using Castrol Edge 5w-40 for a long time in 2 of my cars that have around 100,000 miles on them.
In my 1990 Toyota which has 317,000 miles on it I've been using Castrol Edge 5w-50 just because I figure it has really a lot of wear. So I wouldn't rule that out, just probably depends on your wear level. But I think 5w-40 would be first choice for your climate.
 
Last edited:
I’m with we’re on boost, definitely a 5w40 for as brutally cold as it gets in Canada (and that’s coming from someone in Ohio LOL). I usually hate “what oil” threads but the way he broke it down gives a great technical explanation that supports why opposed to these discussions that turn into an argument of “x brand is the best because” that get nowhere when people really over think it.

Before anyone comes in recommending high zinc racing or diesel oils like Valvoline VR1 or Penn Grade we have to keep in mind this is a daily driven application that’s likely not going to constantly be getting revved all the way out. Castrol Edge as he suggested is a fine selection amongst many of the other big brands, it comes down to pick your poison. Either way being it’s an old engine with old seals I’d stay away from a full synthetic and go with a conventional or synthetic blend. In my dsm I’ve always ran Rotella 15w40 conventional but it’s also stored and not driven from November to April, if it was used in the winter I wouldn’t be using something 15w during those months (and that’s not to start a Rotella debate, been using it for years in a stock non turbo block making over 400 horsepower beating the crap out of it, and know guys in the deep 9s and into the 8s with 4g63’s still relying on it, if it was going to do harm it would’ve done it by now). As far as daily drivers/non performance applications my preference is Valvoline max life high mileage, my 94 Ranger is on the 5w30 synthetic blend and my 06 Crown Victoria is on the 5w30 full synthetic (been on synthetic it’s whole life so full synthetic is a go in that application), with the exception of my 78 f250 that has Rotella 15w40 in it as it is also not winter driven and the flat tappet cam in the old FE engine needs something with high zinc content.

In short, any big brand 5w40 conventional or synthetic blend should do you fine in the winter, with going up to a 10w40 or 15w40 in the warmer months.
 
Thanks for the validation!

I get a wicked discount at Napa because of my workplace discount (Napa autopro) and I'll see what they have for they have for a decent price.

I once ran a liquid moly 5w40 synthetic in the truck. I stopped because it was 75 dollars for 5L. I'll probably buy it again for the laser since it had the ACEA A3/B4 rating.

We do have the Castrol edge up here but the 5w50 I believe is hard to come by.
 
If it uses/burns oil, don't use synthetic.
 
Thanks for the validation!

I get a wicked discount at Napa because of my workplace discount (Napa autopro) and I'll see what they have for they have for a decent price.

I once ran a liquid moly 5w40 synthetic in the truck. I stopped because it was 75 dollars for 5L. I'll probably buy it again for the laser since it had the ACEA A3/B4 rating.

We do have the Castrol edge up here but the 5w50 I believe is hard to come by.
Just a heads up, Napa house brand is rebottled Valvoline. I’d just buy that in a high mileage flavor and dump that in it if that’s what the best deal is. Absolutely no sense in buying a full synthetic (let alone a ridiculously expensive one) for a tired engine as it won’t help a single thing and is more likely to do more bad than good. Like Marty said above, if it’s burning oil a full synthetic is NOT what you want to use, and as I mentioned above on old gaskets and seals that have never been exposed to synthetic the acidity of it can cause stuff to leak more or stuff that wasn’t leaking to start leaking. A full synthetic is NOT the correct choice for your application. A “synthetic means it’s automatically better!” is 100% a false mindset as that varies based on application and when you’re talking our 30+ year old junk it’s 9 times out of 10 not the case.
 

Op is in Canada and will be driving the car through the winter where it may get ran in -10 degree temps and colder on a regular basis at times. Valvoline VR1 only runs as thin as 10w30 (and I don’t know about other places but here 20w50 is all that’s stocked without ordering it), a 5w40 is more suitable to his application. While VR1 is fantastic and they’re my go to for 20w50 applications, it wouldn’t really apply here, especially being it doesn’t sound as if the engine is going to be revved out all the time on a regular basis it’s not at all necessary either.
 
I'll definitely try to find a conventional 5w40 but here that is very hard to come by.

I know I can get a 5w30 conventional way easier than a 5w40. I might just have to go that

Just for the fun of it Is there any issue mechanically using a synthetic blend? Or is it just seals that I'm worried about?

Thanks again
 
Synthetic will show you every leak your motor has, if it has any. Conventional wont.
 
And to answer your question about the BG stuff I see you added later, not worth it. If it is an issue with the rings sealing that might bandaid it, then a few hundred miles later you’re back to the same thing but having ran something through the engine that doesn’t belong there. If you suspect the rings are stuck from it sitting then just run it some as they typically free up and start working again on their own if they worked before it sat.
 
That is really interesting. We sell the b/g products at work and I have seen cylinder pressure increase by 100psi.

After talking with one of the clients we preformed the service on he also said that it was only temporary.
 
When an engines worn it’s worn, there’s no miracle snake oil to dump in it to make it good again. The way I look at it is if you can’t leave these “engine flush” sauces in the crank case long term then they have no business there. Now like I said before, in a case where you’re dealing with something like sticking rings from sitting without running, I’ve personally used stuff off the shelf and seen others use off the shelf products that I whole heartedly believe assists in bringing them back sooner, but again some running and heat cycles with good clean oil and fresh clean fuel they’ll eventually come around anyway, if they won’t no miracle product is going to make it happen. But again, something like rings just sticking from sitting versus wear causing rings not to seal are 2 different things, nothing in a can is going to magically hone the cylinders and re ring the pistons.

Now I will say, I’ve seen on receipts various chain places like Conrad’s, Tuffy, National Tire and Battery, etc charge customers a ridiculous price to dump some 20 dollar can of snake oil in their engine and call a 200 mile band aid “fixed”. Any real shop knows that’s ridiculous and isn’t going to charge a customer for that, but the chain stores have no problem doing that because people who aren’t engine knowledgeable know no different and are willing to pay because they trust someone who they think are an “expert” to fix it and it’s quick money. Just because a so called shop does it doesn’t mean its a good thing or let alone works even.
 
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top