ljd-924SE

regarding the water water/antifreeze/coolant:

i was also concerned with the effect of mixing and what ratios are best so i actually contacted redline. the guy emailed me back saying for warm climate states (such as florida) you should run 75% distilled water, 25% antifreeze and 1 bottle of water wetter year-round for best cooling performance.

KuHL 951

This mixture ratio question came up a lot on Miata.net. The 60/40 +water wetter was preferred due to the need for a stronger corrosion inhibitor ratio since the blocks were cast iron with aluminum head. I'll probably get crucified for this but using an all copper head gasket would worry me a bit for our P-cars. Aluminum/copper is just about the worst combo for galvanic corrosion if the distilled water content is too high. I'm not familiar enough with the HG design to know what the exposure potential is. I do know that several here have mentioned what they thought was corrosion pitting near the top of the water jackets using conventional steel rimmed gaskets. I would make it a point to replace the coolant mix every year if the 75/25 ratio was used; at that ratio the mix would become acidic much faster. I would never mix a 50/50 ratio like most shops do. It just won't carry off heat well even though the boiling point is higher. Nothing will overheat a car in a hot climate faster than too much coolant!

tod84944

Erau and 2Tight, I sent both of you a PM. I have a couple sets of 3 blade and a couple sets of 6 blade. I also have some 6 blades without a shroud.
toddandcharity@peopelpc.com

Granite 944

I did this change over to a double 6 bladed fan assy I removed from a later model parts car (85/2). I can tell you that the noise level is greatly reduced. There was a TSB dated Dec. 6, 1985 (#8526) that tells of doing the changeover. It tells you to replace the hose going to the water pump with the newer style hose (IIRC, newer/later style hose is pn 944.106.237.07 now), or shorten the old one 5 to 10mm. I had to do this also, and it clears just fine. The older hoses will definately interfere, the newer ones won't (shorter on the water pump side, slightly different shape). I replaced the entire housing with the fans. You could do just the fans, but need to check that the position of the fan is correct (plug connector must face down at an angle to the right). Depending on your car, you may have to replace/change the electrical connectors. I didn't have to do that. What the TSB did not address is the fact that the upper radiator hose going to the overflow should be replaced with a later model hose also because the early shape/configuration is really to close to the fan blades on the passenger side and can make contact with fan since fan protrudes slightly out of shroud. The later hose is shaped different, and should clear better. (I didn't have a good hose to use at the time, so I just positioned it very carefully for now). Make sure your fan rotation is correct. Bridge the thermo switch on radiator, and the direction of fans turning should be counter clockwise when looking in the forward direction at the fans.
I had a '83 parts car that PO had wired in a relay and switch to the center console to operate the fans with. My opinion is don't hack it up.......make it work the way its suppose to, just with much better fans. (PO did a horrible job of wiring).

HTH

KuHL 951

Thanks Ken...Great info! I guess I'll look for the whole assembly. Were there any issues with mounting the new assembly or did it bolt up to the same mounting points? I'll have to look at the setup when it's light. I assume the fan setup on my Turbo would be what I'd be getting so I can compare the two before starting. I hope the new fans help out on the cooling issues. Between the new fans and low temp components that's about all I'm going to try. A 951 radiator would be overkill to my budget.

Thanks Again

Charlotte944

A turbo radiator won't work because it won't fit into the NA mount (BTDT).

Porsche went to a 6-blade fan and lower motor speeds to reduce the noise.

On an early car both fans run at high speed whenever the radiator temp switch closes and the ignition is on. When the ignition is off, only the driver side fan runs, and then it runs at a slower speed.

On the later cars the radiator temp switch has two set points. The lower set point runs BOTH fans at low speed, and the upper set point runs BOTH fans at high speed when the ignition is on. With the ignition off, both fans run at low speed.

If the fans are running properly and the cooling system is OK, then as long and the car does not overheat, you should be fine. The main point to keep in mind is that you are always going to see the in-dash temp gage climb while your sitting at a stop light, and the speed of the increase will depend on how hard the car was driven before you came to a stop.

When the car is moving above about 25-30MPH, the temp gage should steady out somewhere between the 1st and 2nd marks.

Going to a low temp thermostat and low temp radiator switch should make the engine run a little cooler, but the temp gage will still go up when you stop, it just won't go as high.

Granite 944

I think Cliff knows his stuff here! I've never had a turbo, but my parts and technical catalog shows that the housings are the same part number for '83 to '88 na's and S models with AC, and a different number for the Turbos (my book only goes up to '88). Maybe there is a depth difference between the two, or a bolt pattern difference due to the fact the Turbo radiators are different? My swap bolted up just fine, no issues that I remember while installing the complete housing/fans assy. other than what I mentioned earlier. If you just come up with just the fans only, they should go right in no problem. If you want to see the TSB on this, I can email it to you if you like.