I notice, after driving the car; the coolant level rise in the reservoir tank. Is this normal or bad?

Thanks

 

depending how much fluid is going in there could be signs of a bad headgasket.

 

i would say about 3 inch above the full mark.

 

Water expands about 5% when heated to engine temperature. So, about an ounce should be coming over to the reservoir. I do not think that is enough to raise the level in the reservoir 3 inches.

 

so it means the car has a bad head gasket? It's been like this for awhile; and there's no mixture of oil and coolant in the engine.

 

It's not a definite but its a possibility, have you done a compression test lately? I think that the radiator cap or thermostat could also cause this. I'd start with a compression test and go from there.

 

Ahhh, brain fart. Five percent of the coolant capacity is more like 10 ounces. My car's reservoir was filled to the full line and I added 10 ounces of coolant. This raised the level 1.75 inches. However, the reservoir is narrower towards the bottom. Adding coolant to a nearly empty reservoir would make a bigger change in the level.

 

Hmm. If it's about 2 inch of rise in level, maybe I don't have a problem at all. LOL. I did compression test last year. The car was good. I noticed when i change to a new stock radiator cap; there is a leak of coolant on the transmission area. I maybe I need to replace all the lines and thermostat?

 

I changed all the coolant hoses on my car at 60K and was surprised how sorta half rotten some of them were. The two big hoses were probably a waste of money. Radiator caps are usually shot after about 30K but that varies quite a bit (I have a tester). I've encountered old ones that still held pressure and new ones that didn't.