Antifreeze

[JoelZ]

I recently bought a 280Z and I am having a problem with the antifreeze/coolant. As I drive the car there is no issue with the temp or anything, but after shutting off the car, a few hours later there is antifreeze on the garage floor. When checking the radiator/reservoir, the radiator was not full to the top and there was just a little in the overflow container. I had the car to the mechanic today for state inspection and he said that he could not find any evidence of antifreeze leaking. I am wondering if it is coming through the overflow tube on the reservoir container? But why would this happen if the radiator was not even full and there was not much in the reservoir. Is there something unique to the 280Z (this is my first one) that would cause this to happen?

Thanks all for any help you might have----JoelZ

[sblake01]

That almost sounds like a bad radiator cap. Have the cap checked to see if it holds 13 psi or just replace it and see if the problem goes away. They're fairly inexpensive.

[ktm]

Your radiator is not full up to the top because it spit up the coolant onto your floor. It does not happen a few hours later, it happens within 5 minutes of shut down. Eventhough you've shut the engine off, the coolant temperature will rise considerably as it is no longer flowing nor is it being cooled. Your radiator cap is suspect and may be failing.

[JoelZ]

Thank you for the information. I think the best spot to start will be a new radiator cap. I will give it a try and see where it takes me...

[moonpup]

You might want to check out the water pump. There's a small hole on the underside that allows water/coolant to escape when the pump is starting to go bad. Look for any traces of coolant under it and along the front of the timing cover and down.

[Pomorza]

Actually had the same problem on my 280z. First check the radiator cap and the water pump like advised above. Secondly check the lower radiator hose where it meets the water inlet(outlet) above the radiator. On my Z this is prone to leak if the hose isn't really on there tight. Also check the hoses at the radiator as they can leak also if they are not on there very tightly.

Jan

[DeesZ]

...... Also check the hoses at the radiator as they can leak also if they are not on there very tightly.

I agree with the suggestions offered.

Tight hose connections are important, but there are potential issues if the radiator hoses are 'over tightened'. I had a leak that turned out to be from over tightening the lower radiator hose. The PO put it on so tightly that it crushed the lower radiator outlet. I had to remove the radiator and reshape the outlet tube after I finally found the problem.

Let us know what you find.

[JoelZ]

Thanks for all the information, here is what I am doing:

I bought a new radiator cap, 13PSI and put that on. I also ordered a new water pump since it was inexpensive and I will attempt to put that on this weekend, I hope. At that time I will check the hoses and connections to ensure all OK there. Thanks all, I will update once all work is done.

[ktm]

Why put the pump in when you do not know the source of your problem? One change at a time. Replace the cap and see if that works. If not, then install the pump. One takes 30 seconds the other 30 minutes.

[Pomorza]

I'm going to have to agree with ktm here. Why replace something if its not broken. But if you wish to replace the water pump by all means go for it. But,

please, please if you are going to buy a new pump replace the bolts with it. MSA sells them for like $4 or something.

The bolts that hold the pump on are not very strong after the many years of expanding and contracting. The likeliness of you breaking one is fairly high and this will lead to more headaches then you really want. I've had the fun experience of having to pull a broken bolt out of the engine block. (as the P.O broke on of the water pump bolts) took me nearly two hours before I could get it loose. So please buy new bolts!

Jan

Edited November 5, 2009 by Pomorza

[JoelZ]

Well, I got a new cap and it still is leaking. It is really weird, after running for a little it does not leak at all then running for more then 10 min or so I notice it leaking again. I looks like it is coming from the water pump area.The other day I drove it about 30 miles or so and I started to overheat due to the leak. I just don't get it. I have a new water pump that I need to get on, and I was thinking, does anyone think that the thermostat would have anything to do with this?

[Pomorza]

OK I own a 76 280z and have had this problem. The easiest way I found to check for leaks, other then to take it to a shop is this. Turn the car on (in your driveway with some sheets or something under it for leaks, preferably white). Wait for the car to reach operating temperature. With the car at operating temperature carefully observe your engine bay and look for leaks. Check the underside of the water pump, the radiator, the thermostat housing and all the hose connections. If you don't see any leaks turn off the car and watch your water pump. With the system still pressurized coolant will flow out of the weep hole if the pump is bad.

As for the thermostat. While your replacing your water pump (and thus have no coolant in the engine) go ahead and replace the thermostat. Takes about ten minutes and its added security. It also wouldn't harm doing a full flush of your cooling system. An obstruction in the radiator or cooling system can cause a hole boat load of trouble.

How over heated did your engine get?

Jan