Coolant leak - gurgling hiss from rat's nest
 

On shutdown I hear a gurgling, hissing sound coming from the middle of the rat's nest toward the front. Then the overflow fills up and dumps coolant because air is taking up space in the cooling system.

The thing is, I didn't think there were any coolant lines in, or under the rat's nest. And I know it is not the curved coolant hose in front of the rats nest that comes from the back of the filler neck.

Where can this leak be coming from? I hate these pinhole coolant leaks. Any ideas? Which coolant hoses run through there?

Thanks for the help. I don't want to take the whole rat's nest out before I have a pretty good idea where it may be coming from. I have tried visually searching for gurgling coolant and wetness under the UIM after only removing the vacuum chamber, and can't find anything. It is deeper down than I can see with a flashlight.

Hope someone can point me in the right direction!
(oh, and I have recently changed the water pump and water pump housing gaskets so it is not coming from there)

Thanks!

The water line from the water pump houseing goes to a metal line in the rats nest then back to rubber that goes to the bottom front of the throttle body .From there it goes through the hot wax rod back to rubber line along the back of the engine to the rear end plate . So check the hose to the rats nest in front . My mechanic said that has been one he has seen bad on several cars .

yep, i just had to replace mine it completely ripped open and was spilling coolant everywhere. I was going non seq so it wasnt too hard for me to replace. it is best to remove the ACV to get to it. its kind of a pain to replace, you also have to remove part of the rats nest which in turn requires taking off the UIM, it really is no fun because you probably will have a good chance of popping a few solenoids if you havent done it before. Good luck man, the heater hose is 3/8 inch and it does run to the top of the throttle body.

have fun! :)

huh? Are you talking about he hose that runs from the TB down to the block, nearest the firewall? Unless you have really big hands all you need to remove is the TB, UIM.

yep, actually. i tried numerous times and I could NOT get to it, hahah. i have good rx7 working hands too long and skinny, but yeah if you can get to it without removing a few solenoids thats obviously going to be much easier and less time consuming. i was removing all the stuff anyway so ya know, it made it easier for me.

Are you speaking of the same hose as duboisr? It sounds that way. And it runs from the water pump housing to the front of the rat's nest on the bottom? Just trying to clarify that we are all talking about the same hose so I will know where to look. I know it's not the hose from the back of the throttle body which is hard to reach. DOes anybody have a picture or a diagram of this hose? I would hate to get it all apart and be unable to find the leak. Thanks again!
John

Also, you don't happen to have a part number for this hose would you? It would help my to look up a diagram in the parts fiche.

The hose from the back of the water pump housing is short and goes to a metal tube attached to the rats nest .That tube is connected to another rubber hose that goes to the bottom front of the throttle body . The top one is common to leak but the one on the throttle body bottom will leak also .

http://www.anodized.com/~clayne/fd3s/medusahead.05.jpg

Here's how you fix it:

http://www.anodized.com/~clayne/fd3s/medusahead.09.jpg

But don't use caps. Drill and tap where the nipples go and use 1/8NPT plugs.

Clayne types , drill and tap and use pipe plugs . My mechanic does his customers cars this way . So there is no chance of a blown rubber plug . On his car the holes are welded up . They are welded on afew customers cars also . Rubber plug, pipe plug , welded, you get the quality you pay for . He also removes the hot wax rod unit and makes a plate to cover the holes .