Throttle Body Coolant Hose Leak?
 

I recently purchased a 1993 FD. It has a downpipe, high flow cat, greddy catback, apexi intake, and AST. The motor has a brand new rebuild with 1000 miles on it, ive put the miles on. I had a leak from the overflow tank from what I believe to be a clogged coolant line between the AST and coolant reservoir. I replaced the AST and the three hoses that connect to it, as well as both radiator caps. Drove it for a couple of days with no problems then noticed a leak comming from the back of the engine. Car has never overheated I installed a Defi temp gauge in the throttle body line when I first got it. I also have the thermoswitch from Pettit. Overheating is not a problem.

The leak happens when I get home or after the car has sat for awhile. It will just start to leak out the back of the motor and will eventualy stop by itself. The only line I can think of is the throttle body coolant line. I can see a small pool of coolant on top of the rear iron by the exhaust side of the car.

Ive looked into how to remove this line and am confident in doing it. Im just looking for some conformation on my logic in singling out the throttle body line. Any other ideas or things to check?

On a side note the throttle body coolant line seems new but is not OEM. I have an OEM one from Malloy already. Just kinda stumped on why 1) it leaks after sitting awhile and 2) why its
not a constant leak.

Best to track down the leak. Get under the car and find it. It should not be that hard to find. Don't guess where it might be.

It probably only leaks once it heats up and expands a bit. Once it's sat a while and cools back down, no more leak. Does it have a clamp on it?

The other location back there that likes to leak is the adapter that plugs into the iron, so it's a good idea to replace that too while you're at it. Think it's like 10 bucks from Ray. Since you said the coolant is on top of the iron it's probably the tb hose like you said.

Thanks for the info on the adapter. Exactly the kind of info im looking for. Ordered one of those from Ray yesturday. Can you still remove the adapter with the intake manifold on?

The plastic adapter plugs into the rear iron, and contains 3 orings inside it (comes pre-installed inside the adapter)

Easiest way to replace it is under the car i'd guess. I replaced mine when I had the engine out.

I got everything taken apart and the throttle body hose that was connected to the rear iron did not have the adapter, it just had the hose running over the nipple and clamped on with a worm clamp. I got my parts from Ray today but I don't know exactly how the adapter goes on. Either way I put it on it does not seem right. Also the hose that I have does not fit over the nipple of the adapter, both the hose and adapter were purchased from Ray at Malloy Mazda.

https://www.rx7club.com/picture.php?...ictureid=37326

This is a pic of the hose and adapter together. Maybe I dont know how they go, I was expecting the adapter to be something different. I was expecting the adapter to slide onto the rear iron and smap on or something like that to indicate a tight seal and then I expected the hose to go over the adapter. The hose wont be able to go over the adapter since the hose has a smaller diameter than the adapter. The only way I could get somewhat of a fit as to slide the hose into the larger end of the adapter, but this too seems like an imposer fit because there would be no way to clamp the hose anywhere.

The following are pics of the hose and adapter to see if maybe I got the wrong parts.

https://www.rx7club.com/picture.php?...ictureid=37325
https://www.rx7club.com/picture.php?...ictureid=37327

I feel kinda dumb not being able to figure this out. If anyone can help I would appreciate it. Also what keep the adapter on the rear iron? The nipple coming out of the iron slides into either end of the adapter but I can wiggle the adapter around like it does not have a tight fit.

The plastic bit is for the heater, left side of the rear plate.

The hose you've got, looks like the pre-formed one that leads to the right hand side top of the rear plate. I've had one go hard and split where it goes over the nipple....it's a prick to install with everything in place. The sheet steel nipple too is subject to corrosion if coolant hasn't been used.

So the plastic part has nothing to do with the throttle body coolant hose. The only thing need to install the hose is the hose then and it just slides over the nipple on the rear iron and the nipple on the throttle body

might seem stupid but check your coolant level. I had a similar problem, turned out I just had too much coolant in.

Thanks for the help. Ive fixed the leak, the throttle body coolant line had a small vertical rip it in near the rear iron nipple area.