94 Q45 Coolant Leak

[psychic_mechanic]

As I pulled in to my parking spot at work today I noticed a coolant smell and a few wisps of steam from the driver's side of the hood.

I only had a few minutes to look, and it looks like the front of the driver's side valve cover is damp and coolant is dripping on to the header.

Is this the dreaded under plenum hoses or is it something simple like a coolant line to the throttle body?

[elwesso]

Could you be more specific on how "in the front" it is...... If its before the TB (foreward of it) there are no coolant lines up there... The EGR-C solenoid and canister solenoid are under that little black plastic covering on the drivers side, then moving back there are some PCV lines going into the top of the VC, then your at the TB..

On the TB there are 2 hoses going into the bottom as a coolant bypass and for the FIC.... There is another coolant line going into the EGR port sort of as a bypass, but that might be farther back...

In my plenum writeup I seemed to focus on the coolant hoses around the TB, but there are 2 coming around the TB but I would think that those would leak down into the valley.....

[DAEDALUS]

Make sure the clamps on the TB coolant hoses are in place.

[maxnix]

In any case, don't drive it until you determine the source. A catastrophic failure would cause a meltdown and that would be horrible.

[psychic_mechanic]

It's on the front half of the valve cover, looks like under the TB. I didn't get a very good look at it.

I have to drive the car home tonight, I'll keep an eye on the temp gauge and top off the coolant before I go.

I've been on vacation for a couple weeks now, and of course the car breaks the first day back at work.

[maxnix]

The gauge will lag severely the actual heat increase of the coolant, so don't trust it. If there is no coolant at the gauge sensor, it will not work at all (i.e.- when it is in full failure mode!). Spray on valve cover is warning of imminent failure.

Safest to flat bed it, or at least stay off Interstate so you can stop frequently to check its status.

Call Joe and order the comprehensive under plenum hose kit. Might want to have the KS and harness also, and the coolant hoses to the radiator (including the anode) and heater hoses on hand. You can return unused items, but I bet there won't be many.

[DAEDALUS]

Another NICO member this year had an overheat that blew his head gasket. There were signs of coolant leaking from this same spot--the clamp on this hose had been moved at some point. Apparently, it was a slow leak that was left unattended for years...it may or may not have led to the overheat.You don't have to remove the plenum to replace the two TB hoses, but remember that coolant hoses are usually in better shape than most others...if one of them has given out, they're all due.

[psychic_mechanic]

Now for the stupid lazy question- which of the hoses on the TB are coolant hoses?

I think the plan for the time being is to replace these sections of hose with over the parts counter bulk hose and order the underhood plenum kit with all the other goodies I should do, adding valve cover gaskets and spark plugs to the list.

Thanks for all the help...

[DAEDALUS]

Look for one that's wet! Hard to work on, but easy to see them. The thing about pre-shaped factory hoses is that they won't kink up on bends.

[psychic_mechanic]

I found and fixed the problem last night.

A piece of 5/16 hose replaced the line from the TB to the EGR thingy that had developed a hole near the TB side.

Time to order some hoses and other goodies.

Now I just need to burn off the sickly sweet antifreeze smell. I hosed the engine down last night, but it still smells.