Fluid flush

[Plain Jane]

I can't find any details about service/maintenance on my '86 Bonneville V6 in recent years besides hushed whispers and hearsay, so I want to start with a clean slate and replace all the fluids. The car is approaching 88k kilometers. Would it be recommended to undergo these flushes, what fluids would be recommended and how much do I need to buy?

I'm thinking:
-coolant
-brake
-power steering
-diff
-engine oil
-transmission oil

I'd also like to install a Transgo shift-kit while I've got the pan off. Is it safe to change the transmission oil at this point? I'm assuming the oil is the very same the car rolled out of the factory with 30 years ago.

 

[Bonnewagon]

Always a good idea to change the fluids. But with the rear end, if there is no sign of leakage anywhere, and the level is good, I'd leave it alone. Check the level through the 3/8" square fitting plug on the side. I just did a trans fluid flush on a 2000 jeep. Changed the filter first, then put a hose on the return line in a bucket, idled the motor, and filled through the dipstick until it ran red. Worked great.

 

[clean8485]

Doing the fluid flush and replacement is a good idea.
Depending on how you intend to do the brake fluid flush, you might run into some problems. If you want to flush the system through the brake screws, make sure that you can get all of the bleeder screws open first. The bleeder screws on the rear wheel cylinders can be problematic, since they're recessed into the back of the wheel cylinder, and that recessed area can get full of dirt, and therefore get quite corroded over the years.
I'd be a bit leery of modifying a 30 year old transmission as well. There's bound to be a certain amount of internal wear in the transmission after this much time and mileage. I'd do the fluid change and service first, and see how the transmission works, before attempting any modifications. Just my opinion.

 

[565bbchevy]

I am currently going through this process with the Regal that I recently bought. I only drove it a mile or so just to get an idea of how much work it needed and to see how the 200R4 shifted (flawlessly I might add) I then started on rebuilding the entire suspension and brake system.
I did replace the rearend fluid since I wanted to put a nice aluminum cover on it anyway and also figuring the original fluid is 30 years old and lubrication technology has vastly improved since 86' and I will soon be doing the trans flush but the only modifications for now will be adding a deep aluminum trans pan and a trans cooler, later when I add some power I might go in and change the valve body.

 

[GuysMonteSS]

I try to change my brake,trans,power steering and rearend fluids every 2 or 3 years.
In a climate like we have in Eastern Canada where we have periods of high humidity and temperature swings that range from high's in the mid to high 30's or more with the humidex factored in and lows of - 20 or colder these fluids can absorb moisture after time and loose the properties that make them work effectively.
Brake fluid is especially hydroscopic,here is a copy & pasted description;
"Well, brake fluid always was, and continues to be hygroscopic - meaning that it absorbs moisture like a sponge. Leave a container of brake fluid open for a few hot, humid summer days, and it will likely absorb enough moisture to render it un-useable according to DOT specifications.
From a brake engineering point of view, absorbing and dispersing moisture throughout the system is good. It keeps moisture from forming in puddles within the system. Of course, these water puddles would settle into the lowest areas - such as wheel cylinders and calipers - where they can easily be boiled into steam by the heat generated by hard braking conditions and cause a loss of braking known as brake fade.
The downside of brake fluid being so hygroscopic is that the moisture dispersed throughout the system lowers the brake fluid boiling point, increases its viscosity, and promotes rust and corrosion."
IMO,a little preventative maintenance such as changing these fluids can go a long way towards increasing the longevity of your driving experience.
Guy

 

[Plain Jane]

Thanks for the helpful replies. I live in Montreal where the temperatures and humidity levels fluctuate rapidly. The car has not been winter driven since 1992 and gets stored for the colder season. That means that the car sits for months on end which probably isn't good for the fluids either. The brake fluid for example is a thick black soup at this point.

Mechanically, the car works fine. It could probably use a carb tuning, and has a habit of stalling when cold with the wheel cranked, but otherwise it runs well enough. Maintenance is my top priority for the moment, but I would like to tweak a few thing here and there just to keep up with traffic (merging onto a highway and passing is always a test of nerves). I have no intentions of building a race car or stoplight dragster, and I plan on keeping the 3.8 where it sits. I was thinking since I'll be changing the diff fluid, I might as well swap in something a little sportier too. However, I'm not too sure what I even have, what will fit or how to do it. But that's another topic.

Back to the fluids, should I be looking to buy a specific brand/s? Naturally I want to best for my car.

 

[jeremyandthemonte]

For fluids I would stick with one brand and normally what I do with oil when I dont know anything about the engine is I run regular non synthetic for about a week or 500k then change it then inspect the oil and filter for anything then I switch to a synthetic.

 

[GuysMonteSS]

If it were me I would go to your local NAPA store and let them help with selecting fluids.
80W-90 for the rear diff and a bottle of limited slip additive if so equipped;
http://www.amazon.ca/dp/B0028CMPIS/?tag=rippca-20
I believe that DOT 3 is fine for the brake fluid,do not use from a previously opened container and do not mix different levels of brake fluid,ie: DOT 3 with DOT 4.
Trans fluid I'm not sure as I run a standard trans and I think it may depend on what trans you have.
Again I'm not sure but I think any type of power steering fluid will work.
Quebec & Nova Scotia share very similar weather conditions so we have that in common.
I have never used synthetic fluids but from all that I have read leads me to believe that switching to synthetic in a higher mileage older car can result in leaks so you may be better off to stick to non-synthetic fluids.
Guy

 

[Plain Jane]

Ok, so no synthetic. I'm pretty sure I don't have LSD. It's your standard no frills GM economy diff (216?), nothing special there.

I believe the transmission is a TH200 3-speed. I much prefer manuals, but I can't be too picky with what was essentially given to me. It's not a car to be driven aggressively anyways, so I can deal with the autobox. A shift kit should breathe a little life into it when I need her to hustle though.

I'll run over to Napa one of these days and see what they can do. Thanks.