‘84 Z28 L69

Had coolant dripping from under the nose forward of the mounting location for the front sway bar and wonder bar. Felt around and the radiator hose felt like it was maybe starting to dry rot. So I started with those. Upper and lower hoses, replaced them with Napa replacements. No leak, no problems, car sits fine with no visible issues.

Until the next time I drive it. Drives fine with no problems, but then I park it and shut it off, come back later to a big puddle of coolant under the car. Tighten up the hose clamps a bit and figure I didn’t get one tightened enough. Add more coolant, everything is fine, drive car, no noticeable issues while driving with frequent stops to check coolant levels. Stop, get out and walk away to work or wherever, come back to a puddle of coolant. Leaking around the same spot.

I am assuming there must be something wrong with the Radiator and it needs replaced based on where the coolant seems to be dripping from. However, I am not discounting the water pump either, even though it is not directly leaking near it so far as I can tell. It is hard to get under there to be sure.

Anyone ever have any symptoms like this? Car sits fine with coolant for weeks or months on end and then springs a leak after being driven and parked again?

Any suggestions would be appreciated as well as recommendations on replacement parts that would be improvements over the worn out factory ones. Thanks in advance for any input.

 

Have you cleaned everything off and pressure checked the system?
How about the "weep hole" on the water pump underside?

 

Where is the weep hole I want to check? I have cleaned everything off multiple times and don’t really notice anything dripping off the engine thankfully. It is always leaking off the cross members under the radiator.

 

Use a mirror to see the weep hole . It’s underside of water pump.

 

The weep hole is inside the pulley. Probably can't be directly observed.

Get up under the car and look at the rear/bottom of the lower rad hose. If you see evidence of coolant running down there, it needs a water pump.

 

Some Pumps Have 2 One On Top One On The Bottom

 

Thanks for the info and pictures, I will check it out when I get home tonight.

 

Check for the good ol signs of coolant tracks. that nice white crusty train on the hose... the pump could be leaking and dripping on the hose sending the coolant away from the pump.

Probably your radiator though.

 

Probably the radiator... Once the drip hits the frame under the radiator, it can go anywhere... Loves to run horizontally...

 

My theory: It's probably the radiator. People sometimes fail to realize that the coolant temp/pressure increases for a short time after you shut the car off. If there is a small crack in the radiator, it might not show itself while the car is running because coolant is being cycled. Once the car is shut off, the coolant stops cycling and the temp & pressure goes up just enough for it to be pushed out of the radiator.

My car just went through this. Car was running good with a small puddle of coolant periodically forming. Came back from a short drive after swapping the front brake pads, and a line of coolant was leading from the middle of my driveway up to my car. Found a very small crack in the radiator end cap spraying a mist of coolant. Hopefully my new DeWitts radiator will be here next week.

 

If this is the original radiator, or one constructed like it (aluminum core, plastic tanks, rubber seal between them), then this would be my guess too.

 

Yes, absolutely investigate any possible path for coolant to escape. Don't ignore any potential opportunities to find the leeeeek.

Start by laying up under the front of your car and looking at the lower rad hose. If it's utterly devoid of any signs of coolant running down it, then, look farther. If coolant is running down the bottom/back of it, then ... change out the WP first and foremost. THEN move on to the next possibility which may include the rad.

THEN AND ONLY THEN, move on to radiators and all such as that. Don't get me wrong; don't put words I didn't say (type) into my mouth (keyboard); only, do the simplest stupidest eeeeeezyest possible thing there is to do, which is, LAY UP UNDER THE CAR AND LOOOOOOOK UP.

Yes your rad may be fornicated. No it may not. But don't jump to conclusions one way or the other until you LAY UP UNDER THE CAR AND LOOK.

LOOOOOOOOOOK.

 

Life has been busy, I purchased a new water pump for the Z28, and it is sitting in the car, in the garage, waiting to be installed. I decided I was just going to do the water pump and radiator both because there were signs of both potentially having issues when I crawled under and looked.

Any recommendations on radiator? Guy at the parts store recommended a multi-core radiator replacement over a repro of the original. I could use some info on this please. I did my due diligence and read as many radiator topics as I could find. Most were talking pros and cons of a champion radiator, but were well over a decade old. Could there be a preferred option now that most agree is best?

My car is an L69 with the T5 if that matters. Thank you in advance for any further assistance.

 

If you got one of those all metal / copper? ones, you can take it to a rad shop and have them give it a "tune up" I do that with mine. That way you know it fits and cools well. Might as wel lchange the t stat and thoroughly flush the system while you are at it too.


Bad thing about aftermarket / performance stuff is ftment cause then you need to modify / cut things sometimes.

 

I replaced mine recently. Went with a DeWitts. They seemed to have the best reputation along with Be Cool.

 

Dewitt’s, haven’t heard too much about that one. I will try to track that down, thank you for the suggestion.