There's coolant in that there hole?

[GTOger]

As you may have read elsewhere on this forum, we just took the ZR-1 on a nice little trip and put about 3k miles on her. The car performed flawlessly the entire way.

Then the weekend we get back, the car starts running rough. Stumbles at idle. Backfires when you lift off the gas. Shakes. Rattles from the top end. It's not itself. Every time I've had opportunity to be under the hood it's been dark. Tonight I got out some lights and had a look.

One of the first things I notice is a wet spot on the underneath of the hood. It's roughly over the back passenger side spark plug. Uh oh.
http://farm6.static.flickr.com/5140/5560191602_030e580ecc.jpg


Then I look around and find:
http://farm6.static.flickr.com/5107/5560189006_0135e8226e.jpg

And this:
http://farm6.static.flickr.com/5027/5559612671_5cdeb87957.jpg

And this:
http://farm6.static.flickr.com/5307/5559613377_b5a5541bc7.jpg[

A very careful eye will detect areas of green coolant around the bolts and in the valley and it looks to me like it has come from somewhere in the vicinity of that back passenger side plug.

Tomorrow afternoon I will pull it and see what I can find, although as we all know the visibility into that plug hole just plain stinks.

Avid readers may recall the wife and I pulled the plenum and did an injector replacement on this motor just before Christmas time. We've put somewhere around 3500 miles on the car since then. It sure is gonna stink if we have to pull this thing apart again.

Advice and suggestions, as always, are welcome and encouraged.

[carter200]

My vote is new gasket install time. Make sure and get the best gaskets you can find. Good luck ...

[GTOger]

Super. Which gasket sets do you figure I'll need to order? My guess is I'll go back to Jerry's Gaskets since he has treated me well so far.

Man... 5k miles I've put on the car and I'm tearing into it for the 2nd time. I'm hoping it's not because the car hates me.

[VetteMed]

Super. Which gasket sets do you figure I'll need to order? My guess is I'll go back to Jerry's Gaskets since he has treated me well so far.

Man... 5k miles I've put on the car and I'm tearing into it for the 2nd time. I'm hoping it's not because the car hates me.

Definitely head over to Jerry's, he will take good care of you as he has before.

I've had to pull the plenum in my current Z at least 5 times in less than a year of ownership, and less than 500 miles - it's a matter of getting the bugs worked out, but don't despair, once it's "right" it's really RIGHT.

[carter200]

I'm not the expert but with help from Jerry or Kurt you'll be in good hands. You must have been good to her and she wants to be stroked one more time ;)


PS: Nice choice on the Goat and HD!

[GTOger]

Thanks VetteMed & Carter200. I guess I ought to go ahead and do the plug wires as long as I've got the plenum pulled. (sigh) now I wonder what else I ought to be spending money unexpectedly on!

[todesengel]

Yuck, a gto? GTO's are for sissy's ya know :cheers:

[A26B]

You might check the small coolant line that tees into the RH side of the plenum & runs forward to the T/B and towards the rear of the engine as an alum tube that turns toward the upper coolant tank, connected with a rubber hose. From the looks of the hood & the cam cover, i would be more suspect of that line & hoses than a gasket.

[sammy]

i agree,it may be something as simple as you didn't tighten the worm clamp enough when you had the plenum off .if its not that then the rubber line or that aluminum line fas gotten a crack in it

[Paul Workman]

You might check the small coolant line that tees into the RH side of the plenum & runs forward to the T/B and towards the rear of the engine as an alum tube that turns toward the upper coolant tank, connected with a rubber hose. From the looks of the hood & the cam cover, i would be more suspect of that line & hoses than a gasket.

That would be my vote too! And, one could always rent a coolant pressure tester from AutoZone, pressurize the system and see where the leak is coming from ... Maybe with a little help from a spray bottle and some soapy water, if the coolant level has dropped below the level of the leak..

Just a thought.

P.

[Aurora40]

I don't know why an external line leaking would cause the car to run rough, though. Have you started it with the hood up to see if you can see it spraying?

FWIW, if you pull the plenum, you may want to take the starter out and give it a good cleaning, get all the coolant out from under it, and dielectric grease up the connections. My starter gave up the ghost shortly after a major coolant spraying incident.

[PhillipsLT5]

Good call Jerry, the rubber on that line will probably be dry after 20 years, try to tighten clamp

[GTOger]

Interesting thoughts guys. I've got a "prior engagement" until 2pm today, but then I can take a good look at the car. There are a lot of things I'd prefer to having to pull that plenum again so soon, so you better believe I've got my fingers crossed. I'm anxious to have a look!

And, oh... todesengel.... "pbbbbbbbbt"! :)

[A26B]

One of the subject hoses on mine split while driving & wouldn't you know the split was on the inboard side & sprayed directly under the plenum. What a mess.....the one place you wouldn't want it to go. When the engine is hot, there's no way to releive the pressure & LOTS of coolant went under the plenum. I replaced the hose, but fried the starter. Was able to push start & limp home. What a mess.

This may not be the problem, but the coolant passages in the injector housings are to the front of the engine, likewise on the plenum.

[Paul Workman]

This may not be the problem, but the coolant passages in the injector housings are to the front of the engine, likewise on the plenum.

To Jerry's (very good) point, there is no coolant passages in the plenum or the IH near the location of you leak. All the more reason to suspect it is not the gasket, or at least not causing the problem seen in the photos.

And, further review of the photo seems to confirm that the spray pattern was external from the motor; the concentration of the fluid staining seems to center on a spot on the cam cover with what appears to me to be splashing radiating from that spot.

If you got coolant pooling under the starter, you wouldn't want to try to crank 'er until you pulled the starter and blow it out with compressed air if water did get into it.

Just a thought...
p.