Originally Posted by slader99 (Post 58518)

Symptom: Coolant leak @ rear engine, hoses and clamps are all fine, coolant running down EGR cover. (Note: Mrnickleye pointed out that coolant doesn’t pass behind the EGR cover… Tightening the EGR cover will NOT remedy any coolant leaks in this area.)

I have read several posts on the forum stating the tightening/removing the heater union banjo bolt is impossible while the head is on the block, engine in car. For this minor coolant leak, removing the head adds an unacceptable amount of cost and manhours to the fix. It can be done with a 32 mm socket, 3/8” breaker bar, Drill + 13/16” bit, or dermal without removing the head. Below is a picture showing the heater union and the procedure for fixing this leak. The “union” consists of a union, a banjo bolt, and two washer/gaskets.

1) Go to your local autoparts store and buy a standard 3/8” drive 32mm socket.
2) Drain about 1L of coolant from the Rad.
3) Remove the hose clamp and hose from the top of the banjo bolt.
4) Place socket over fitting to make sure it clears the firewall.
5) You should find that the socket slips over the top of the banjo bolt and bottoms out on the top of the banjo bolt before engaging the 32mm head. If you are unable to slip the socket over the banjo bolt, you purchased a non-standard socket that is too tall, return it for a shorter socket.
6) Remove socket and using drill or dermal, remove about 1/4” material from the inside of the socket creating a 13/16” diameter recess for the heater union banjo bolt. (Note: If you are using a 13/16” bit, be aware that the shape and hardness of the socket material is going to seriously affect the life of the drill bit…..)
7) Blow out the chips, slip the socket over the union (it should now engage the 32mm section of the banjo bolt) attach your 3/8” breaker bar and determine if the bolt is snug. The spec is 43ft.lb. That means if your using a 12” breaker bar you should be pulling on it with about 40lb of force. My union was noticeably loose, so I tightened it and it fixed my leak. Be warned that if you strip the threads out of the head it will be an extremely expensive and time consuming mistake. TIGHTEN WITH CAUTION. If you found this fitting was loose, do your hose back up, top off your coolant, congrats your done, if not, on to step 8.
8) So you decided that your union is already as tight as you feel comfortable with. Remove the remaining clamp and hose from the union, and then remove the union assembly. You will need two new union washers. You are going to need to use grease to stick these unions in place, or better yet, hi-temp silicon.
9) Smear your washers with high temp silicon to stick them to either side of the union. Smear additional silicon on the top and bottom of the union assembly and add the banjo bolt. Put the assembly in place making sure that you don’t knock the union washers off the assembly or your leak will be worse than when you started, if you used silicon or grease you should be fine. This is defiantly the trickiest part of the procedure; it’s sounds easier than it is.
10) Tighten the banjo bolt, attach your two hoses. If you used silicon, it’s probably worth waiting an hour or so for it to set, if you used grease continue on.
11) Top off with coolant and fire her up. If you still leaking coolant, must have been from somewhere other than this fitting!!!

Sorry for the length of this essay, hope it helps!

Originally Posted by ddmcse (Post 64546)

i would guess the heater core is rotten , problem is they practically build the supra around the heater core