I have noticed that the coolant level is 2 inches higher on the dipstick after driving home from work. It used to go up only a couple lines on the dipstick when warmed up. The coolant was changed and burped by a mazda tech 7000 miles ago.It dosnt run hot,leak coolant, white smoke,or have any bubbles when i remove the rad cap.I just ordered a 94 t-stat,because i have read on this forum that it was better than the 93 model.I think i will have it prof flushed by machine when i get the new cap.Any ideas on why it is doing this now?

 

Your engine may be running hotter than it used to, or the new coolant somehow may expand more as it heats up than the old mix did. Or, it could be as simple as a change in the angle of the dipstick as it measures the coolant level so that it is now more verticle in the tank.

As long as the coolant level in the reservoir tank is at "Full" when the car is cold and returns to the "Full" mark on the dipstick after the car is fully cold again, you should be OK.

 

Coolant expands into the tank as it heats up. Antifreeze expands more than water. If your new mix consists of more antifreeze you'll see a larger change in the overflow when the car is at operating temp.

Mine sits probably 4/5's up on the dipstick's hash marks when its hot. That's NPG-R though which expands quite a bit.

The overflow is nothing to get excited about. As long as its not overflowing all the sudden when everything was previously fine and there's no coolant disappearing from it then everything is A-OK.

 

Got a Question? Looking to get my self this fc and the guy tells me that after about the 45 mins whille the car is running the collant light or someother light comes on and the coolant res starts to fill up. He has had it for 10 years probably never changed the coolant. He only put about 50000 over the past 10 years. I think it just need to be flushed and thats what he has told me. Do youll think this is the case, that it just needs to be flushed?

 

An FC or FD? Either way, tell him to have it flushed and if it fixes it you'll buy it. I wouldn't buy it on a hunch, that could be the sign of coolant o-ring failure.

-Charlie

 

Its a FC. Alight i understand, I found out how to test to see if the o ring on a thread so ill going to call guy later and see whats up. If the it is the o-ring it would have white smoke when started up. Correct? Thanks again.

 

I saw and test drove it today. It does not smoke at all and the coolant hasnt not been changed in the past 10 years and is mostly just water in the res tank.

 

Sounds like a science project.