Civic overheating issue

[Miles ruud]

I have 97 civic dx with the non vtec 1.6 engine, and for some reason it is leaking coolant from the top of the overflow tank. The theremostat and cooling fan both work as they should.

I have also pressure tested the system and found no other leaks.

What could it be?
I havent tested for a head gasket leak, but my oil looks fine, as do my exhaust fumes

Topic

[kevin gosselin]

Don’t want to change anybody’s thought but what is the mileage of the vehicle and how long did you have it for.

I just saying that as a coolant flush/maintenance point of view.

there is 2 possibility right here. either you have a headgasket/combustion leak in the system. A 5 gas analyzer would point that out rather than the little kit you get that change color. If it’s a minor leak you will have to push you engine to duplicate the problem. Maybe take a picture of your plug so we can maybe help you there to confirm a cylinder that could be problematic.

The other possibility is to have a partially plugged radiator. If it’s partially plugged it won’t really have any symptom at city driving as the coolant flow is not really that high as the engine doesnt produce that much heat anyway. But come high rpm and highway speed, even when the air flow through the radiator, the radiator won’t do its job as the hot coolant will be restricted right after the T-stat… it will take more than just a 5 minute road test, the only time that you would see the temperature starting to rise is when you would be coming out the highway and then going back to city driving temperature will raise the fan would kick in and not even stop. I had a mazda MPV over 200’000 km that did that to us. it would drive for sometime 15 to 30 and up to 1 hour before it would happen, the customer could really explain us its driving habit but it was always driving for a long time at a steady speed.

On his model the radiator is a 1 row aluminium with plastic tank… being said the inside row look kinda allright at first, tstat was replace by the first tech who work on it, spark plug look fine. The only way I maybe could see a difference would ve been to use a garden hose and spray the radiator to see if it as effect on the temperature but by the time I got back from the road test there is coolant overflowing so there is air in the system.

I don’t know if your civic as the half size radiator or full size but that might be one thing that I’ve been missed. Once we replace the radiator on that mazda… I saw the radiator in a half and there is 3/4 of the channel that were plugged. Being said a flush might remove some sediment but what is plugged is plugged… A guinea pig test would be to remove the radiator and empty it.. but it face down and fill it with CLR let t soak overnight and flush it the next day… but you would need to pressure flush it to force the crap out… at that point might as well replace the radiator…. a heater core would be more realistic as it is smaller and the time to replace those can sometime be quite long.

I just though I share the experience.

[EricTheCarGuy]

That sounds like an airflow problem or a restriction in the cooling system. Make sure the fan is working and that there are no obstructions in front of the radiator. If they’re aren’t any, then perhaps you have a restriction somewhere or your water pump isn’t working correctly.

[Author]

Replies