P30 transmission cooling lines routing

[WayneG]

As I am working on other repairs on my 84 Excella, After I had the radiator out for flushing, I decided to replace the cobbed up transmission cooling lines. They were spliced with compression unions, rubber hoses and a inline filter. I am guessing because in its history, it has had a engine change and then the transmission replaced.

I am wondering if my lines are not installed correctly? The radiator is a cross flow type and my lines go to the drivers side of the radiator. That is the hotter side.
I noticed that there are plugs on the passenger side of the radiator, and there is a heat exchanger coil inside.
I looked in the Chevy P30 chassis manual and they show the lines running to the passenger side.

My question is, for owners of P30 chassis with cross flow radiators, do you have your lines on the drivers or passenger side?

I would think it would make more sense to use the cooler side of the radiator to cool the transmission.

[mayco]

Mine are on the passenger side.

[mayco]

Do your tranny cooling lines enter the cooler at the top or the bottom?

[WayneG]

Originally Posted by mayco

Do your tranny cooling lines enter the cooler at the top or the bottom?

Assuming you mean the transmission fluid flow, I am not at the vehicle now and I am not sure if the the supply line is going to the top or bottom of the radiator.
I would guess that there would not be much difference temperature wise top to bottom since the coolant would be about the same temperature as it is coming from the engine and the glycol cooling only happens as it passes to the other side through the fins.
Cooling from the Passenger side at a lower temp makes sense, I need to find out if it may be a problem leaving it on the drivers side. i will stop at a tranny shop today to ask.

[gunner]

On mine the lines come from the Transmission on the Driver's side then are routed across the back side of the bottom rear of the radiator and go into the Radiator on the Passenger side.

[choctawmel]

My 'Silver Bullet' do not go to the radiator. The PO put an Allison 545 in and Allison uses a large cooler in front of the A/C condenser. I added a electric thermostat controlled fan cooler under the bumper for the engine oil and another cooler in the fender well behind the right headlight for the transmission (before it goes to the one in front of the radiator). My idea is to get as much heat away from the radiator as possible. Maybe a roof top A/C:
Red Dot Rooftop Units from Harold Electric Could paint it silver

[WayneG]

Originally Posted by gunner

On mine the lines come from the Transmission on the Driver's side then are routed across the back side of the bottom rear of the radiator and go into the Radiator on the Passenger side.

It sounds like there was no standard routing for these lines. Of course it may depend on the engine and transmission combo, or whoever serviced it last? Mine is a 454 with the TH400 tranny.
I did stop by a transmission repair shop today (With someone old enough to give an answer on the topic) He said it is better to have the cooling on the cooler side of the radiator, but it should not harm the transmission on the other side. I hope he is right, because I cant budge the plugs in the other heat exchanger on the passenger side, so I hooked up the replacement lines as it was. BTW The hot tranny fluid comes from the lower fitting on the TH400 and goes into the bottom port on the radiator.

Here is how Chevy suggests the transmission lines should be run for the 83-84 P30 chassis

[choctawmel]

You don't have an engine oil cooler? The original radiator in 'Silver Bullet' had plates in both tanks. Cool side was transmission, hot side was engine oil. The new aluminum radiator I replace it with only had a plate (not used) in the cool side. Had to have a fitting welding on the hot side for the high temp electric fan switch which turns on the A/C fans if the water gets to 223 (I think) degrees, the fill hole welding shut and a fill nipple welded on the front.

All works good and with the aluminum radiator, intake, and water pump she lost about 100 pounds off the front. Only way I can loss any weight. Maybe by the time I need to loss more, they'll have titanium parts

[WayneG]

Mine has, what I think is a aftermarket oil cooler on the drives side, attached to the grill, no extra fan.
My AC heat exchanger had dual 12" fans controlled by a thermostat inserted in the upper radiator port. The fans were dead when I got it, they were mounted with the wires pointing up so water ran in and corroded the contacts. I just bough a single 16" to replace it.

When I had my 77 Argosy(s), I hauled stage, sound and video gear for festivals, To make room for the ton of gear, I pulled the fridge, roof AC, engine AC and the spare tire, I did keep the kitchen sink , but left the girlfriend home

[DaveFL]

Mine go in the drivers side but I also have a separate radiator mounted on the drivers side and it's supply line comes from the passenger side. Included with the separate radiator is an oil filter.
Tracing lines back and the drivers side lines come out of the engine not the transmission right next to the motor oil filter. When I opened the lines it looked red and smelled like transmission fluid. Like you mine have compression, aluminum, rubber and to hide or protect some of the aluminum they put them in sleeves.
When I looked up the lines radiator in my big chevy book it talks about two separate side radiators one for trans and one for motor oil but optional.
My question to add to the problem are those tanks totally isolated from the main engine radiator???
I am trying to trace down a water leak into the main engine and it would be nice to know how it is getting there.
To make it worse there is a a/c radiator between the main and the auxilary add on one. So I have 5 radiators in the space engineered for 1.

[WayneG]

The mini heat exchanges on each side of the main radiator are nothing more than coiled tubing connected to the fittings in the end caps they are in a bath of the engine coolant.

If you have a coolant leak into the engine oil, I doubt it would be through the heat exchanger. To take that out of the equation, you could always put on yet another separate heat exchanger for the engine oil.
My guess would be that you could either have a leaking intake manifold gasket or head gasket. Not a fun repair. If it is a very minor leak, you could take a chance on a good stop leak additive, but that can cause other problems. If it is a intake manifold leak you may get off easy with re-torquing the bolts, but even if those methods stopped it, it probably would not last for very long.

If you need to get a closer look at your radiator, and they routed your a/c lines like mine, you just unbolt the a/c heat exchanger and swing it up like I did in this photo.

[DaveFL]

Originally Posted by WayneG

If you have a coolant leak into the engine oil, I doubt it would be through the heat exchanger. To take that out of the equation, you could always put on yet another separate heat exchanger for the engine oil.
My guess would be that you could either have a leaking intake manifold gasket or head gasket. Not a fun repair. If it is a very minor leak, you could take a chance on a good stop leak additive, but that can cause other problems. If it is a intake manifold leak you may get off easy with re-torquing the bolts, but even if those methods stopped it, it probably would not last for very long.

Put on radiator pressure tester, found a leak, forward most bolt head holding down the lower intake, put the torque wrench on it to check by setting to 20 pounds and the torque wrench unscrewed it without resistance. So you are right on two counts torque and intake gasket.
Have most of the stuff off the top of the engine, will replace as the job of getting to it and not replacing doesn't make sense. In my research found the bolts also need a thread sealer besides two rounds of torqueing.

As a side note the 1999 454 is weird in it's head torqueing, needing 3 and very specific torqueings, very different from earlier models.