Multiple fluid changes

[111]

I need a new water pump, so I will be draining the coolant and adding new along with WaterWetter. I have a new Mobil 1 oil filter and plan on using Mobil 1 synthetic(though I would like a suggestion as to the weight). The brake fluid is already changed, so I suspect I only need to change the manual transmission fluid and the rear differential.

If you all could list what you use and/or what is recommended for fluid changes I'd appreciate it as that is going to be my Fathers day weekend project.

Also the amounts of fluids would be great (i.e. how many quarts of oil, etc.)

Thanks

 

[111]

Come on guys, even if you do not want to recommend all the fluids, at least tell me what you are running in your MG's.
I have owners manuals to all my cars except this one so I have no idea what is recommended from the factory.
I want to head down to the store and buy all the different fluids in one trip, and change everything out the same day for piece of mind having just gotten this car.

Thanks

 

[GaryBeu]

Well...I'm awfully new at this also, but here's what I did after some research. I'm pretty confident that it's correct.

Engine: 3.75 qts.Pennzoil 10w-40
Transmission: 4.5 pints Pennzoil 5w-50
Differential: 2.25 pints EP90 gear oil
Radiator: 1.5 gal. 50/50 antifreeze

Do you know how to check the transmission fluid level? It's sorta weird so let me know if you need help finding/doing that.

Cheers...Gary

 

[111]

I think you have to unscrew the plug on the thermostat housing, assuming that is where the thermostat is located to add or see if the coolant is high enough. :wink:

Oh wait, I see you asked about checking the transmission level. No, I am not sure how to do that.

As to the other fluids, I am hoping to find a high zinc content oil in Mobil 1, and I will most likely use Zerex original formula for the coolant as I know it is designed for older cars with protection for brass/copper which I think the MG has?

As to the transmission fluid, what brand is everyone using? I see you listed Pennzoil 5w-50, but isn't that motor oil? I'd like to go with synthetic, but if that has not been used with success from the MG community, I can go with conventional fluid.

 

[JPSmit]

not sure what the zinc content of Mobil 1 is 0- but found this

From a forum on Bob is the Oil Guy:

"Mobil 1 15w/50 contains an adequate amount of lubricants and anti-wear additives for old-style valve trains."

And direct from Mobil....

https://www.mobiloil.com/USA-English/MotorOil/Files/Mobil_1_Product_Guide.pdf

From the above guide (April 2009):
Mobil 1 15W-50
Nominal phosphate PPM = 1200
Nominal zinc level PPM = 1300
Boosted, higher viscosity, fully
synthetic formula designed for
performance vehicles.
HT/HS applications.
Racing and Flat tappet
applications.

For those of us in the far flung colonies who can't get Valvoline 20w/50 VR1, the Mobil 1 15w/50 what I've been using the last couple of years (and also pleased to have finally found a source for Wix filters).

I only know Midgets so am not sure about transmission oil.

 

[ralph_s]

FWIW.....I use 20W50 Valvoline w/ ZDDP. For the tranny I use straight 30W. I don't believe anyone recommends synthetic in the tranny!

 

[fogliner]

Hi 111;

I hope this helps...The tranny dipstick is located at the front end of the tunnel,just behind the firewall, a small flap of the carpet flips back and you can reach down into there and pull a small dipstick upwards,it has 2 O rings i beleive and its a pain to reach but once you do it once its not bad.
I put a wire tye looped through the ring for easier fishing just to have something to grab ahold of.
I use 20/50 oil in my engine and transmission.I don't use additives because I have an overdrive and any antifriction additives are not recommended in the tranny oil...just straight 20/50.tranny oil feeds the overdrive unit to engage it.
I filled my tranny through the dipstick hole using an extention tube rig i got from wallyworld that fit the cap on my jugs.
In my diff i used synthetic 80/90 if i remember but it has been a year or 2.

 

[111]

not sure what the zinc content of Mobil 1 is 0- but found this

Thanks, I always try to use Mobil 1 oil, so I will pick some up in that weight.

--------------------------------

When you guys say 20w-50w transmission oil, are you referring to the same motor oil you put into the engine, or is it some type of oil made for transmissions?

Hi 111;

I hope this helps...The tranny dipstick is located at the front end of the tunnel,just behind the firewall, a small flap of the carpet flips back and you can reach down into there and pull a small dipstick upwards,it has 2 O rings i beleive and its a pain to reach but once you do it once its not bad.
I put a wire tye looped through the ring for easier fishing just to have something to grab ahold of.

I filled my tranny through the dipstick hole using an extention tube rig i got from wallyworld that fit the cap on my jugs.

What the heck, that sounds like a tough job to check the level, much less trying to fill it up like that. It's a good thing you let me know because I would have drained the fluid and had no clue how to fill it back up. I do not like to shop at Wally World, but the filler tube that connects to the oil jugs sounds like a winner.

 

[PAUL161]

I've always used 20/50 in the engines and 20/50 in the transmission/overdrive. It's what the factory recommended and I've never had a bit of trouble using their recommendations. The TF will get the same oils. They built, tested and raced the engine and transmissions, so I guess they knew what they were talking about. I use to use Castrol, I now use Valvoline racing oil 20/50. zinc PPM-1192 1077. AMSOIL racing oil seems to have the highest zink PPM rating at, 1599 1288, but it seems to be a little harder to get. PJ

 

[111]

I've always used 20/50 in the engines and 20/50 in the transmission/overdrive. <span style="font-weight: bold"><span style="text-decoration: underline">It's what the factory recommended</span></span> and I've never had a bit of trouble using their recommendations. The TF will get the same oils. They built, tested and raced the engine and transmissions, so I guess they knew what they were talking about. I use to use Castrol, I now use Valvoline racing oil 20/50. zinc PPM-1192 1077. AMSOIL racing oil seems to have the highest zink PPM rating at, 1599 1288, but it seems to be a little harder to get. PJ

Well that is good enough for me. The only question as it relates to the trans fluid is if you can put 20/50 synthetic as opposed to conventional which presumably the factory used. Is the Valvoline you use synthetic? I do not have OD, so that is not an issue if that is a reason not to use synthetic.

 

[PAUL161]

Not that I have anything against a synthetic oil, I guess it's just that I've never used it and always used, as you put it, conventional oils. My Chevy pickup I bought new in 93 and it now has 195,000 miles on it and still uses no oil! My Ford Ranger with a 4 cylinder engine in it has 225,000 miles on it and only uses about a pint in 3,000 miles. neither engine has ever been apart. BUT, The oil in my vehicles never exceeds 3,000 miles before a change. I don't know how synthetic would act in the transmission, especially with an overdrive. Some fellas might have tried it. I always go by the old saying, if it aint broke, don't fix it! Even though the new oils are supposed to be better than when these cars were built, I've had no problem with the factory recommendations, so why change? I only use a racing type oil because of the high zink content, no other reason. It's not supposed to be used in a car with a cat converter in the exhaust, it'll plug it up over time. PJ

 

[111]

I hear what you are saying, and I know from other cars I own, motor oil can be a very subjective thing which can lead to heated debates. For this car I'm sure I do not need top of the line synthetic oil, but I've gotten so use to using it in all my cars, I just feel more comfortable. Funny enough I used Castrol 20-50 in my older cars and never had any issues. Then again I am like you and change my oil frequently, every 3-5k. I swiched to Mobil 1 sythetic back when I bought my ZR-1 and they recommeneded it for the LT5, which is a very expensive engine to repair/replace.

I picked up some Valvoline high performance SAE 80W-90 gear oil for the differential. I'm assuming it will be fine, so all I need to buy now is the oil for the transmission. I guess I will just pick up some conventional Castrol 20w-50 for it, and use the Mobil 1 15W-50 full synthetic in the engine with a Mobil 1 oil filter.

So that others can benefit from the information in this thread, I will assume that the following posted earlier are the correct amounts of fluid and viscosity recommended by the factory for our cars;

Engine: 3.75 qts. 20w-50
Transmission: 4.5 pints 20W-50(Motor oil)
Differential: 2.25 pints EP90 gear oil
Radiator: 1.5 gal. 50/50 antifreeze

If it is a little off, please post what you are aware is the recommended amounts and/or viscosity.

 

[JPSmit]

I am far from an expert but I seem to recall synthetic can be a problem in transmissions. too slippery I think and can bother the syncros. I don't think you can go wrong with conventional.

 

[111]

I am far from an expert but I seem to recall synthetic can be a problem in transmissions. too slippery I think and can bother the syncros. I don't think you can go wrong with conventional.

I've heard that to, so no sense in taking a chance with an old transmission to begin with.

 

[Airbornevet]

I have used 20w50 Castrol GTX in my 71 B engine since new. I have used synthetic 20w50 in the trans (OD unit) and synthetic 80w90 in the rear end since 1983. Never have any problems. I use the synthetic for longer change intervals. As for the transmission top plug, which is a bear to get to and get out, I put a heavy duty tie wrap around the top of the plug ring and just insert a long screwdriver and pull up to remove.

 

[Steve_S]

Because you asked, I run Classic Car Motor Oil in four of my MGs and Mobil 1 in another. I highly recommend against changing from dino to synthetic in a higher mileage engine. You risk serious issues if the synthetic knocks old chunks of crud loose within the oil passageways.

To address a couple other comments in the thread, Castrol GTX has reformulated several times over the years. It no longer has the level of zinc that is considered necessary for our old engines. Running it won't create problems overnight, but in theory will accelerate wear in the valve train. I suspect Paul doesn't actually run racing oil in his engine, as that would be totally inappropriate for street use, but more likely something like VR1 which says "racing oil" on the bottle. These type of oils aren't really racing oils, they just use the term to sell oil to sports car owners. VR1 does have a decent level of protection however and it isn't a synthetic.

For other fluids, I run Royal Purple in all my M.G. rear ends. The MGA, MGBGT and MGC gearboxes get Castrol 20W-50 while the MGB gets SAE30-ND. Brand isn't really critical here, in my opinion.

You can run synthetic in a gearbox, many use Redline. However do NOT use it in a Laycock overdrive because the friction modifiers will be too slippery for the clutch cone.

You should really buy a repair manual, as it lists all the fluid types and quantities necessary. Some of the fluids will be outdated of course, but the general type and how much to use will be covered. It also shows procedures, torque specs, etc which are all things you should have on hand while working on your car.

Paul, as a side note, your TF should use MT-90 gear oil or equivalent in the gearbox, not engine oil.

 

[swift6]

I suspect Paul doesn't actually run racing oil in his engine, as that would be totally inappropriate for street use, but more likely something like VR1 which says "racing oil" on the bottle. These type of oils aren't really racing oils, they just use the term to sell oil to sports car owners. VR1 does have a decent level of protection however and it isn't a synthetic.

I think the VR1 is marketed as much, if not more to muscle car owners as sports car owners (much larger market). Regardless, I agree it is not true racing oil. You can't buy true racing oil by the quart on the shelf of your local auto parts store. The upside though is that the VR1 on the shelves not only have the appropriate levels of zinc, but also the additives that make it like any other oil on the shelf in regard to using them in regular street engines.

 

[emmett1010]

Hi 111
The transmission filler plug is on the passenger side of a 1980 MGB transmission. They discontinued the filler with the dipstick that was used on earlier models. You fill the transmission until fluid runs out of the filler hole.
80/90 gear oil is very close in viscosity to 20/50 engine oil. I use it in my transmission as well as my differential, primarily because its easier to pump out of my 5 gallon gear oil container with hose and hook.No problems in 50 years.
I use the VR1 20/50 in my engine.
Its probably more important to check/change it regularly than anything else.
Good luck with your new ride-
Emmett

 

[Sebring222]

Emmett- FWIW I've been using Mobil1 15W-50 in MG engines from prewar to 18V MGB engines for 27 years with great results. I also use synthetic gear lube (Mobil 1) in the differential and Redline MTL in non-overdrive transmissions.

Jim D