MTF change + overheat, Civic 1990

[Félix]

Hi.

I want to change my transmission fluid on my 90 Civic, but I searched online and it takes 10w30 oil, not Honda MTF.
Since I don’t know what kind of lubricant is in there and it has not been changed in probably a very long time, is it a good idea to do it at all?

Also, I think my fan sensor or relay is broken because my fan never comes on. The other day I was in bumper to bumper traffic and the car overheated badly. I pulled over as soon as I could, but at that point the coolant was overflowing from the reservoir and the second before I parked the engine didn’t rev down. It drives normally but is there something that could be damaged, such as spark plugs, pistons, etc… ?

Thanks

Topic

[college man]

see if this helps.

http://www.ericthecarguy.com/faq/what-to-do-when-your-engine-overheats

http://www.ericthecarguy.com/faq/solving-automotive-electrical-problems

http://www.ericthecarguy.com/faq/solving-transmission-problems

[Félix]

Thanks.
The part about transmission fluid helps a bit, basically always go with Honda MTF but is that also true for the older cars? Mine is a 1990.
And what if it has been running on 10w30 for years, is it a good idea to switch for Honda MTF now?

About the overheating, I am not actually looking for the cause of the overheating, which I know, but for the damage that could have been caused by it, if any.

[college man]

[quote=”Boisclair” post=101935]Thanks.
The part about transmission fluid helps a bit, basically always go with Honda MTF but is that also true for the older cars? Mine is a 1990.
And what if it has been running on 10w30 for years, is it a good idea to switch for Honda MTF now?

About the overheating, I am not actually looking for the cause of the overheating, which I know, but for the damage that could have been caused by it, if any.[/quote]

if its had the 10w-30 in it and calls for it. I would use the 10w-30.
As for the overheating. you could have a warped head or head gasket issue.

[Félix]

Ok thanks but I will word my questions differently.

1. I dont know what kind of transmission fluid I have in my 1990 manual Civic, and it has probably been there for a while.
Do I go with the spec 10w30, Honda MTF, or is it best to leave it?

2. My engine overheated badly in bumper to bumper traffic because the FAN doesn’t come on. It overheated to a point where coolant spilled out of the reservoir and the engine didnt rev down when I released the pedal after pulling over. The car runs fine but was there any damage to the engine? Do I have to change the oil or spark plugs…?

Felix

[Ken]

Amsoil Synchromesh baby! Do it! Same weight as 5W-30. It’s all I’ve used in my small manual transmission cars. It can even increase your fuel economy. If you had some degraded, super thick 75W-90 or something gear oil in there that shouldn’t be in there, and replace it with Amsoil Synchromesh, you’ll see a world of difference. Get your MPG readings before and after. That’s the most satisfying part. My Ford Festiva actually called for ATF in the Manual Gearbox in the owner’s manual, but like I was going to do that, pft. But at the end of the day, it shouldn’t make too much of a difference. But there is a world of research and conflicting opinions and favorite fluids people have, like GM Sychromesh/Pennzoil Synchromesh and this, that and the other. At the end of the day, just put some fluid in, and live and let live.

The 10W-30 specification is 25 years old. Today’s advanced fluids, and Amsoil’s Synchromesh will be like space age rocket fuel for your 1990 Honda. It’ll be great.

[Félix]

Thanks.

So you’re saying there is no chance that the Amsoil could cause damage to my maybe worn transmission?
There’s a lot of nightmare stories of people who go out of spec on the manual fluid.

I am really not looking for any gain, just preventative maintenance and not causing any unnecessary wear.

Felix.

[Ken]

Oh no way. All those small 4-cyl. engines and transmissions are pretty much the same, under 2 liters, FWD, etc. You know, that ancient spec of 10W-30, most cars back then used 10W-30. But 10W-30 is pretty much obsolete now and almost no modern cars run it. Motor oil has just gotten space ages ahead of what it used to be. Most Fords used to call for 5W-30, but now most of them, even the biggest baddest engine will take 5W-20, which if you had said that twenty years ago, they would have called you crazy and said it was too thin. Now Ford says that even older Fords, ten or so years, that say 5W-30 on the oil cap, can take today’s 5W-20. Toyota the same thing, and I’m sure other manufacturers. A lot of older Toyotas will say 5W-30 on the cap, but now Toyota says you can use 5W-20 or 0W-20, depending on your climate (Alaska or South Florida).

I know a guy who puts 0W-20 motor oil IN HIS MANUAL TRANSMISSION GEARBOX. Lol, it’s a Geo Metro, and he hasn’t had any problems. He did it for fuel economy gains. You can head right over to Ecomodder to be introduced to that wild world. I think those guys are cooler than the guys with their ridiculous Hondas scraping every speed bump and small pebble in town. Instead of modifying their cars to be faster and more obnoxious and loud, they modify their cars for incredible fuel economy gains. Gasoline engine cars getting upwards of 80mpg, no joke.

Anyway, Amsoil Synchromesh is supposed to be 5W-30 in weight, and it is a manual transmission fluid, and it’ll be great in your 1990 Civic. If you’d like to learn more about engine oil, and how ridiculously boring it can be, go over to Bob is the oil guy, where you’ll find hundreds of mentally ill men who obsess about these details! I should know. It’s just insane and it makes me sick and I just want those hours of my life back. But I did learn that Royal Purple is terrible. So that makes me feel good. Especially about that guy I knew who changed his oil every 3,000 miles with RP, lol.

[Félix]

Wow that is a thorough answer. Thanks alot and I will try the Amsoil if I can get my hands on it.

Felix

[Lorrin Barth]

There’s lots of special gear oils for manual transmissions. Some work very well and some are a disaster. I used one of the latter and had to buy a new transmission. Use what the manufacturer recommends.

[Ken]

[quote=”barneyb” post=102780]There’s lots of special gear oils for manual transmissions. Some work very well and some are a disaster. I used one of the latter and had to buy a new transmission. Use what the manufacturer recommends.[/quote]

Wow I’m very curious. What kind of car was it, what did it call for, and what did you use?

[Félix]

Ahh this is what I’m talking about. I think I’ll just chalk the whole thing up as a mystry of life, not change my fluid and not ask for trouble.

Thanks everyone.

Since I last logged in, I tried changing my rear drum brakes, struggled for a while with the first drum only to realise that the parking brake was on, and finishing without any sunlight. Now I have a rubbing noise… Thing is with drum brakes it seems like no tutorial will work unless you actually have your brakes open in front of you.

[Ken]

“The gear oil, on an atomic level, is made of long-chain molecules that prevent wear by literally keeping the gear teeth from contacting each other. Over the thousands of miles of driving the shearing action of the gear teeth tends to chew up these long chain molecules. The fluid loses viscosity and breaks down, decreasing the ability to prevent wear.”

—

“Running motor oil (10W30, 10W40, etc) in a transmission won’t wreck it outright, but it will require you to change out the oil far more frequently than you would if you ran a gear-specific oil.”

[EricTheCarGuy]

I would suggest you ignore all other suggestions about what fluid to use in your transmission. Only use Honda MTF in that transmission. You’re much better off. If you read the Honda service manual it says you can use 10w30 but Honda MTF is the preferred lubricant. I’ve seen many issues caused by using lubricants other than Honda MTF. I’m speaking from experience here. BTW, I’ve owned manual Hondas going all the way back to the 1979 model year. I’m also a Honda master tech with over 15 years experience.

As for the overheat. It does sound like a fan issue. You need to trace the circuit back to find the cause. If you know the fan can operate, then you might try this. The 90’s did have issues with the fan switches mounted in the lower radiator. If you jump across the terminals and the fan runs, then I would replace the switch and recheck for the issue.

As for the rear brakes, it’s likely the rust on the drum is coming into contact with the backing plate. It’s quite common after a brake job. You might consider cleaning up the edge of the drum to get rid of some of the rust to see if that cures the issue. As for a tutorial, it’s very similar to this.

More information on all of these problems here.

http://www.ericthecarguy.com/faq/solving-transmission-problems

http://www.ericthecarguy.com/faq/what-to-do-when-your-engine-overheats

http://www.ericthecarguy.com/faq/solving-automotive-electrical-problems

http://www.ericthecarguy.com/faq/solving-brake-problems

http://www.ericthecarguy.com/faq/diagnosing-noises-in-your-car

Good luck and keep us posted.

[Author]

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