Did all '55 Buick dynaflos have a cooler? I have just purchased a 55 Special and it does not have a cooler but seems to be plumbed for one. The guy who sold it claims that not all dynaflows came with coolers so he should not have to supply one.

Can anyone confirm that?

Also where might I find one of these things? Can I substitute an aftermarket air / fluid cooler?

I think the seller is wrong,1955 with Dynaflow has a Oil cooler 4.128 no 8523158.
Leif in Sweden.

Dynaflows definitely had oil coolers. In 1955 and earlier they used heater hoses off the water pump to take cool water from bottom of the radiator tank and circulated it to a heat exchanger on the rear of the transmission. I think there was an extra hose nipple on the bottom of the radiator tank to handle the heater/defroster hot water circuit. I do not know for sure, until I look it up, when the crossover to hydraulic lines to the radiator came into use and the heater hoses were eliminated.

Joe, BCA 33493

Thanks, I thought that was the case but wanted confirmation. The trick now is to find a cooler.

Try Wheatbelt Buick. 580-855-2449.....Bob

Thanks, I left them a message and haven't heard back yet.

If you are not concerned with originality, get an aftermarket cooler which will cool much better. The original cooler was barely adequate in normal driving, but was ineffective if driving in mountains or towing.
I love my Buicks but this was a peace-poor design: the hottest water in the engine was directed to the 'cooler' instead of the coolest water from the bottom of the tank on later models. You can also eliminate about 20' of heater hose. If you need the direction of flow of the transmission fluid it goes from the front of the transmission thru the cooler to the back of the transmission.
Willie

Willie,
Did you mount something near the transmission? Which cooler did you use? Someone suggested you need a fan if the cooler is not mounted in front of the radiator.

I used one similar to THIS and seems to work well, but a big one in front of the radiator would be better. Just Google or Ebay 'transmission cooler'.
Willie

1956 was the first year to pipe the transmission fluid to the radiator for cooling.

Willie
How ling was your cooler?

Archie
I cannot get out to measure for a while, but find a spot to mount and measure what will fit.
Willie

Well I finally got the stock trans cooler. Now to check it for leaks and figure out how it's susposed to mount.

I'm thinking of fitting one to Irene. I see a unit on local Ebay. Will hose clamps be OK for the pressure or should I go for one with screwed ends ?

Well after getting a stock cooler I'm rethinking what to do. I have heard that the coolers tend to fail and really make a mess as the water gets into the trans. I have scrounged parts from one such trans and heard someone else describe the mess.

It really doesn't take much to put a conduction cooler on the frame rail which I hear works fine.

Archie--I would not condem the stock cooler because of fear that water will contaminate the trans fluid...if a leak occurred it would be the other way around. The trans fluid is in excess of 15psi and would contaminate the water if there was a leak...which I have never seen.

Ken--Hose clams are fine, just use heavier tubing made for trans fluid.

Willie

Fluid would go both ways, I think, in the event of a leak. Oil woud get into the water when the car is running due to higher pressure in the trans. Water would get in the trans oil when the car is not running, since the radiator keeps some pressure as it cools down and the trans is not turning.

All of which is not to scare you from using the stock one. At least having looked over my '54 and used the stock one for years and years, it seems like a very sturdy unit. And I have never heard of one fail. You can always have it tested at a radiator shop to be sure.

Maybe the stock one is not so effective, though. My plans are to run the fluid through a long aluminum cooler first - the kind constructed from a single tube with inner and outer fins to take away excessive heat, and mounted inside and down the length of the left frame rail, which sould get enough air circulation while the car is under way. Then through the stock cooler to give it some temperature stability. The engine coolant may even warm it back up again in cooler conditions, but gives it some stability.

As far as I understand it, you can be too cool, or too hot. The trans and the oil both like a constant temp in the middle, somewhere in the low 200's.

Since the torq coverter does so much work on a Dynaflow, I think added cooling is a good idea, especially on long grades and bad traffic. Hopefully my plan will work...

Happy wrenching,

Doug Cook

Doug,

That explination would seem to validate what I have seen and heard. I scavaged parts from a trans that was filled with fluid turned to pudding. I believe this was caused by water contamination. I also corresponded with a poster on another board who had the same problem.

I think your point about too cool is also correct. I was considering using a thermostat bypass on the cooler to keep it from being too cool.