I have a 1991 CRX HF with a DOHC ZC engine in it right now and I’ve noticed that I’m losing some coolant somewhere. The car is basically an endless project so it doesn’t really get driven. I’ll fill the radiator up in the afternoon and check it the next day and it will be down about 1/2 a quart or so.

I don’t think it’s something with the engine because about 3 weeks ago I had a different DOHC ZC in it and I noticed the same coolant problem with it.

Is there anyway to check to see where it might be leaking even if there is no noticeable leakage or coolant around the engine?

 

do you get a mad puddle on the ground?

 

No, no puddle and that's the weird part. I can't firgure out where the leak is coming from. Since the problem spanned across both engine I'm thinking it might be a hose or some thing that might have gotten a hole in it.

 

Possibly the water pump leaking?
My SOHCleaked like crazy and i was trying to figure out where it was coming from, turned out i needed to replace the pump

 

It's done this on two separate ZC's so I'm sure both of them couldn't have leaky water pumps.

 

Use a cooling system pressure tester..
Some auto supplies have them in their rent/loan a tool program.

It is a small hand pump that screws on like a radiator cap
and applies pressure to the system..

Test or replace the radiator cap also..

 

Check ur radiator it might be mess up
i worked on radiator for 2 years so i'll check that

 

Hmmm what about the radiator cap, usually I've started the car up and warmed it up for a while and then left it overnight. Maybe it's leaking.

I can also check the double check, tighten the lower radiator hose just to be sure

 

could be the rad. cap, could also be the heater core, make sure your carpet isnt getting damp..if it is, it is the core

 

have you checked your coolant drain plug?

 

have you checked your coolant hoses into the cabin. Have you looked at the inside of the car for any strange leaks.

 

Head Gasket, and yes multiple engine can have the same issue as they are all close to the same age and mileage.

 

i also think this is the problem with my motor. best thing is i probably only have 3 more months to run this bad boy then part out time.

 

Compression test it. If no coolant is leaking out, it can only be going into the cylinders. It could be your head gasket as was suggested above.

 

I don't think it's possible to have a blown head gasket on two completely separate engines.

I did replace the radiator cap, tightened all the hoses and the radiator drain plug and filled it back up, I'll check it tomorrow to see if it's gone down any.

 

i do, you dont know how these engines were treated or ran prior to you receiving them.

 

True about the treatment of engine but the car isn't driven and mainly just sits there for days at a time. Would it still lose coolant just from sitting there without the engine being turned on?

I didn't start it today after filling the radiator back so I guess when I check it tomorrow and if it's still down then it's something with the radiator or the hoses leaking. If it's still topped up without starting it then maybe I could see the head gasket being an issue.

 

Unless you are really unlucky! I doubt that both engines would have the exact same head gasket leak though, but I don't know ZCs too well. So is the coolant disappearing without the car running? There just aren't too many places it can go. Are you sure all the air was out of the system?
If you're driving it and the coolant is disappearing, it points toward a leak that is probably small and is happening under pressure. When I got my car, it was slowly losing coolant and it turned out to be a screwdriver hole in a rad hose that only leaked at higher rpm. The water pump could also be leaking under pressure if it's on its way out.

 

possible that its leaking from the lines. check and replace all of them. pinhole lines are a bitch. i got one and didnt like the outcome......

 

Check the heater core. Same thing was happening to me.

 

If it was the heater core, where would it be leaking at? Passengers or drivers side floor? I can check that tomorrow when I check the radiator fluid levels.

 

DING DING WINNER!

So I replaced the radiator cap with another one I had, filled the radiator back up last week, let it sit for a couple of days, took the car out for a very extended test run a couple of days ago and have been checking the fluid levels ever since. So far it hasn't moved and it looks like it was just a leaky radiator cap.

 

ive got it. someone is stealing it! haha

 

Also check the radiator where the cap seals, the inner part can deform due to steam.