Golberg’s 4AGE 16V Cooling Guide - Lots of Photos!!

[Golberg]

I spent quite some time gathering bit and pieces of 4A-C and 4A-GE cooling systems. I currently have a complete water system(apart from radiator) for an AE71 4A-C, AE93 4A-GE, and a JDM AE86 4A-GE and part of an AE82 4A-GE system.

The aim of this guide is to show the similarities and difference between each of the systems and to give tips about what can be used in different configurations.

Comparison

Water Pump:
A front wheel drive (FWD) 4A-GE water pump off either an AE82 or AE92/3 is fundamentally different from a rear wheel drive (RWD) 4A-GE pump from a JDM AE86.
To begin with, the RWD pump is taller than the FWD pump (i.e. Sticks out further from the engine block). The RWD pump also has better bearings in order to support the weight of a pump mounted radiator fan. Note: If you attach a fan to the front of a FWD pump it will soon fail and no longer function. Interestingly, a RWD 4A-C water pump is almost identical to that of a RWD 4A-GE pump. The only difference is the position of the little ridge on which the cam cover sits.



Water Pump Rear Housing:
Once again the FWD variety of the 4A-GE rear housing is very different to the RWD version. It consists of only a single large water inlet (from theromstat) and an outlet which bolts directly onto the front of the 4A-GE block. The RWD version on the other hand has in integrated thermostat just after the water inlet as well as a bypass inlet from the front water outlet on the head. There is also another inlet which comes from the heater core and had the same outlet bolted onto the block. The RWD 4A-C rear housing is identical to that of a RWD 4A-GE one.



Water Pulley:
A FWD 4A-GE has a pulley with a smaller offset than the RWD 4A-GE one in order to compensate for the shortness of the FWD water pump. The RWD 4A-GE one is considerably more offset. The RWD 4A-C version has the same offset as the RWD 4A-GE one but it uses a single V belt rather than a 5-rib belt.



Front Water Outlet from Head:
Both FWD and RWD 4A-GE versions have outlets that point forward from the front of the motor but on the RWD version there is a short bypass pipe which goes directly down into the back of the water pump rear housing. On the FWD version a small bypass pipe runs down the length of the block to a remote thermostat. A RWD 4A-C has a short outlet which points out perpendicular to the length of the engine and a bypass pipe slightly longer than the RWD 4A-GE version which goes into the water pump rear water housing.



Rear Water Pipes: (from the back of the water pump rear housing)
As mentioned before, the FWD 4A-GE has a large inlet pipe coming from the remote thermostat. The RWD 4A-GE system has one main pipe which comes from the heater core, it also has some smaller pipes which direct water into the throttle body. The RWD 4A-C pipe is just a single return from the heater core.



Rear Water Outlet from Head:
There are 2 different FWD versions of this outlet the AE92/3 4A-GE has a pipe which protrudes out further from the block than the AE82 4A-GE version. The RWD version from an AE86 4A-GE is very similar to the outlet from an AE82 4A-GE except the outlet pipe is longer and has another small pipe coming off it for the throttle body. The RWD 4A-C one is not at all similar to any 4A-GE version.



Thermostat:
As mentioned before the RWD 4A-GE pump housing rear has a thermostat integrated, again this is the same as a RWD 4A-C one. The small inlet pipe from the radiator does not have any provision for a temp sensor and is the same for both RWD 4A-C and 4A-GE. The thermostat for a FWD motor on the other hand is different, it is in its own remotely located housing, there are 2 different types, one from an AE82 and the other from the AE92/3. They are fairly similar and both have provision for a thermo sensor on the inlet.





Alternator Bracket:
There are 2 main different types of alternator bracket for the 4A-GE the FWD one bolts on at the bottom of the block and sits the alternator relatively high. And adjuster strap is mounted to the front water outlet from the head. The RWD one on the other hand bolts to the same place but sits the alternator lower and has an adjuster strap mount on itself. It also has one extra bolt, sitting on top of the RWD engine mount. Why does this matter? You cannot run a RWD water pump and rear housing without it, otherwise the inlet will be blocked by the alternator.



Harmonic Balancer:

RWD Harmonic Balancers are different to the FWD AE92 version. The inner part of the pulley has a greater diameter on the RWD version. What this means it that the alternator will more than likely be pulled closer to the block on a RWD engine but I can confirm that the standard AE92 4AGE harmonic balancer works just fine with the RWD alternator bracket and strap.

[Golberg]

FAQ

Can you use a RWD 4A-C water pump on a RWD 4AGE? Yes, you just need to file off a little of the timing cover ridge and you must also use a RWD rear pump housing too.

Can the RWD 4A-GE rear water pipes be used on a Small Port 4A-GE (100kw) motor? No, unfortunately they cannot, they interfere with the knock sensor on the block. (Work-around in the next section)

Can the RWD 4A-C rear water pipe be used on a RWD 4A-GE? Yes, it can, but it wont allow you to run the throttle body cooling. Same problem as with the 4A-GE pipes on the Small Port in standard configuration also.

Is there any way to keep the FWD alternator bracket when using a RWD water system? Maybe, but it’ll require some modification of either the thermostat input pipe or the bracket itself.

How can I incorporate a temperature sensor (for a thermo fan etc) into my RWD water setup? By using one of the thermostat inlets from the remote thermostats of either the AE82 or AE92 you can use the inlet pipe in place of the regular one which has a temp switch built in.

Can I use a FWD pulley on the RWD water pump? No, if you do the belts will not line up.

Do I need the proper RWD head rear water outlet to run the RWD water system? Yes, unless you do not wish to use the throttle body cooling part.

Can I use the front water outlet pipe on the head of a RWD 4A-C on a RWD 4A-GE instead? No, it will not bolt onto the 4A-GE head.

Can the bypass pipe leading from the front water oulet to the rear pump housing of a RWD 4A-C be used on a RWD 4A-GE setup? No, but it would probably be possible to shortern it to fit.

More to come, just need to think of some more. If anybody has any questions ask in this thread and I'll add the responses here.

[Golberg]

RWD Water System on a Small Port 4A-GE

As some may already know, you cannot use RWD 4AGE heater return on a 4AGE with a knock sensor (small port, GZE etc). I devised another plan which was to use the heater return off the 4AC RWD and twist it 180 so that it sat off the block and also sat lower than the sensor. Here are a couple of photos to explain.

You can see here the small amount I had to lop off to make the pipe fit in (otherwise it just goes straight into the sandwich plate):



I cut up an old battery strap to make a mount for the pipe and it works brilliantly:



The rear outlet joins straight onto the heater return in my pic because I need to drive the car before I get the heater box back in.

[PULSE]

Awesome, thanks for putting in the effort to write all this up! Much appreciated.

Cheers, matt

[Grega]

rep for you
i did my 100kw motor cooling setup like this (same as karl's setup)

[The Witzl]

Yep - the old Witzl method (totally plagarised from ira11y) is probably the cheapest and easiest to do, as the parts used are common as anything.

Useful comparison pictures though!

[Golberg]

rep for you
i did my 100kw motor cooling setup like this (same as karl's setup)

That definitely is the cheapest method of converting a FWD water system for use on a RWD ( and it should work just as well). The RWD system if obviously neater, but its much harder to find the bits(second hand) and new parts aren't cheap. Luckily for me I just stumbled across all of it (from different places) and ended up costing me the heafty sum of $60, Except it was another $70 for the pulley from toyota .

I've made a correction to my orginal post now, as it turns out, the AE92 FWD pump does have the same impeller blades as a the RWD 4AGE one so they can be put on either housing. The 20V ones are different though but thats another story.

[Grega]

i would have shelled out the $$$ for the complete RWD setup, however its the middle sucker in this picture and the pipe that goes between the two that you can't get anymore :

[cri_ag]

nice info dude, +rep. so how would one go putting a smallport pump onto a 4ac rear housing? to gain a cheap neater rwd setup?

[Golberg]

nice info dude, +rep. so how would one go putting a smallport pump onto a 4ac rear housing? to gain a cheap neater rwd setup?

Well, it wouldn't actually end up all that much cheaper, you would still need the RWD top head outlet and the RWD alternator bracket but yes it could be done.

[cri_ag]

ok why cant i use the smallport outlet? alternator bracket is easy, longer belt and modified bracket should do the trick right?

[Golberg]

ok why cant i use the smallport outlet? alternator bracket is easy, longer belt and modified bracket should do the trick right?

Sorry, the picture orginally given doesn't show exaclty why, I've uploaded another. Circled is the bypass pipe outlet which goes down through a short peice of pipe into the water pump rear housing. The FWD version does not have this and you need it.


What is special about the RWD alt bracket is that it positions the alternator lower, this allows space for the thermostat inlet pipe to fit(otherwise it'll hit the alternator). What you will also find is that once you change to a RWD top outlet there will no longer be an adjuster strap on that for the FWD alt bracket as the RWD one has it built into the bracket.

One area yet to be investigated by myself is by using a FWD alt bracket and a custom mounted strap with a 1G thermostat inlet (which goes off at a right angle) you may be able to keep more of the FWD setup.

[Golberg]

I've added a bit about the harmonic balancer, sorry no pics there as I don't own an AE86 one.
Also added the small port RWD section.

And corrected my reference to "temp sensor" into "thermo switch"

[PULSE]

Just to make it easier for a noob like myself, would you be able to make a quick list of all the cooling system parts needed to convert a FWD smallport to RWD. From reading your guide I've gathered that I need a RWD 4AC water pump and rear housing. Would it be worth buying these parts new from toyota/an auto store or if I grab them off an old 4AC will they be fine?

It's all a bit confusing at this stage but I got my engine today so once I have a good look over it tomorrow I'm sure it will all start to make sense.

Cheers, Matt

[Golberg]

Just to make it easier for a noob like myself, would you be able to make a quick list of all the cooling system parts needed to convert a FWD smallport to RWD. From reading your guide I've gathered that I need a RWD 4AC water pump and rear housing. Would it be worth buying these parts new from toyota/an auto store or if I grab them off an old 4AC will they be fine?

It's all a bit confusing at this stage but I got my engine today so once I have a good look over it tomorrow I'm sure it will all start to make sense.

Cheers, Matt

For bigport 4AGE, to do it properly you'll need all the RWD parts listed above apart from the harmonic balancer and you'll be able to substitute the water pump housing and water pump for the RWD 4AC variety. Personally I'd get a new pump whatever you do unless its come off an fresh import motor in which case you can probably get away with a second hand one.

To buy all these parts off Toyota new you are looking at serious $$$ I wouldn't be surprised if you paid over $1000 for all the stuff new. (You'd be better off buying an import AE86 motor which already had the stuff on it)

To do a cheaper version you'll need a RWD 4AGE top outlet, alternator bracket and pump pulley (those are the expensive bits) to go with that, a RWD 4AC pump, rear housing, bypass pipe and heater return and an AE82 4AGE rear water outlet. Note: with this setup you wont be able to run the throttle body water supply. Unless you rethink it a little (which I am doing for my smallport 4AGE to connect it). This last paragraph also applies for smallport 4AGE as the RWD 4AGE heater return doesn't fit onto a smallport.

Some of these things can be very hard to find second hand, I somehow fluked it and got a lot of it for cheap. I got a RWD 4AGE pump, rear housing, heater return an rear outlet with a disassembled engine I paid $150 for. Got a second RWD 4AGE heater return, front outlet, rear housing and bypass pipe for $10. Got my alternator bracket for $56 (i think it was) off eBay and a pulley from Toyota for $70. So I got the whole system for about $150 in the end, if you look around and wait a while you can probably get it for $200 odd. Took me 3 months to get it all. One other note, turned out my RWD 4AGE pump was stuffed so I'm running a brand new RWD 4AC one now which cost me $46.