Auto conversion; now overheating

[JMT240KGTR]

Gents,

Converted my car to 3 speed auto over the weekend. Took it out for a drive last night and to work today and the damn thing overheats, BAD.

Now I've retained the same thermostat that was used with the manual box, but I'm thinking along the lines of longer warmup times for the auto-incorrect thermostat ie too long to open.

I'm using the clutch type fan in good condition (doesn't spin freely when warmed up) and the radiator is good.

I've also bypassed the heater for the time being, need some new hoses for that.

Engine is L28, slightly modified.

Can anyone shed some light, my brain is tired!:classic:

James

[St.stephen]

wouldn't you also need to use the radiator from the automatic as well to run the fluid coolant lines?

[JMT240KGTR]

Correct, that's what I have.:classic:

[Fun_in_my_z]

did you put the cooler unit back into the car? is everythang hooked up?

[JMT240KGTR]

Cooler unit...radiator?

Everything is hooked up properly, don't know whats going on though!

I originally had an electric fan cooling the radiator, might put this back on:cry:

[Fun_in_my_z]

my 74 260 z has auto with two radiators the mane one with a smaller one.

[Bambikiller240]

Sometimes, it's the simple things. Are you positive tha the fan belt is properly adjusted? Bolts at Alt tightened properly?

Had this happen to me once................once!

[zeiss150]

Yo Yo, UUUUMMMMM, you put a 3 speed auto in a Z .... Just wondering why someone might want to do that. Im not bagging on you, just .... wondering. as to the heating problem are you sure your radiator is still good or is it a three or four row?

Good luck.

Matt

[speedyblue]

When it is warmed up, run your hand over the radiator tubes and make sure the whole thing is the same temperature. There might be some crud in there blocking up a few tubes and reducing the area it cools with. At least then you can be sure that the whole thing is working properly. I had a car where the bottom third of the radiator didn't heat up because it was blocked. The tubes ran horizontal on it though.

[280zx Fever]

Originally posted by zeiss150

Yo Yo, UUUUMMMMM, you put a 3 speed auto in a Z .... Just wondering why someone might want to do that. Im not bagging on you, just .... wondering. as to the heating problem are you sure your radiator is still good or is it a three or four row?

Good luck.

Matt

No he put a auto into his ugly 240k

Shouldnt this go in your 240k special section ?

[sblake01]

I have had problems with TEM-couplings (fan clutch) in the past. Just because they don't spin freely when warmed up doesn't mean that they are working properly. With the car hot, rev it to about 2k and hold it there. If the fan clutch is good, it should be locked in at that point until the temperature begins to go down. If it slips out, then it's bad. Bypassing the heater should have no effect on cooling. If your car cooled okay with the electric fan, and it doesn't now, I would suspect the fan clutch.

[JMT240KGTR]

Thanks for the replies fellas,

I've found the thermostat was no good, so this has been removed temporarily for a couple of days. Car runs better now, nice and cool although we are going through a warm spell here so it's OK for now!

Went to the wreckers and sourced a Mitsubishi trans oil cooler which I'll be fitting tomorrow, along with my original 3 row

non- auto type radiator and new thermostat, this will keep things cool all round.

zeiss150, the 3 speed auto is standard fitment behind most L series engines including the Z and although a little slower off the line it has a final drive ratio of 1:1, same as the

4 speed manual, doesn't rev too high at all with a 3.54 diff.

From a source here in Oz there was a L6 series powered Skyline back in '85 that utilised a 4 speed auto trans (not electronic, bonus!), maybe one day I can get one of these. For the time being, and maybe for a while yet, the 3spd will do, my 5 speed was wearing fast (very noisy) so a replacement was in order.

James