Radiator Fluid Level Decrease

[RipRocK]

When I filled up at a gas station up a few days ago, I checked my fluids and I noticed that the radiator fluid had decreased to the low level mark, whereas in the past, it was always right near the high level marker. I checked the level again the next morning after it had been sitting in the garage overnight and the fluid level was the same, at the low level mark.

I always check my garage floor for any signs of leaks and there've been none so far of any. I did have a jug of the OEM radiator fluid handy, so I topped it up, bringing the level back to the high mark.

When I dropped my Pilot off yesterday morning for an intermediate service, I inquired the service advisor about it and he said that as the radiator fluid gets older, the water in the fluid is evaporated slowly and that can bring the fluid level lower.

So, I asked whether I should perform a radiator fluid flush and he said that given the current mileage (74,000KM/46,300mi) and the length of ownership of the car (since Aug/2K2), I can wait at least another year or so.

But if it were up to you guys, and having seen a reduction of the radiator fluid level like I have, would you go for a radiator flush or wait like the service advisor had advised?

The manual recommends the first engine coolant replacement at 120,000mi/192,000KM, but I just think that's way too long to wait before the first flush. What would you guys do? Thanks for your time and courtesy.

[Oh, and mods, if this post should be merged with another thread discussing engine coolants, please feel free. Thanks.]

[john802]

Have them pressure test your cooling system to find out if there's any leakage.

[N_Jay]

Originally posted by john802
Have them pressure test your cooling system to find out if there's any leakage.

First time top it up with some Honda premix.

If it happens again, get a pressure test.

There is no reason to change the fluid early if it is not contaminated.

[jay]

Originally posted by N_Jay


First time top it up with some Honda premix.

If it happens again, get a pressure test.

There is no reason to change the fluid early if it is not contaminated.

I agree. Some evaporation over that period of time is normal.

[sblvro]

I think that is normal. If the level is low when the engine is cold and goes to the upper level when it is hot then the system is okay. But if it stays at the same level whether the engine is hot or cold means there is a leak somewhere and the radiator might be low on coolant even if the reservoir says otherwise. I would not recommend flushing it at all. The original coolant provided some sealant to the system and prematurely flushing it just takes out the protection it provides.

[hondaman2]

in the newer hondas (2001 and up) it is not necessary to flush the radiator until 90,000 miles or more depending upon your vehicle and year.

All vehicles experience some kind of water evaperation when the engine gets hot, cold all the time. So it is normal for the fluid level to be low.

same with oil. if you drive at excesive speeds for long periods of time(80mph and up) your engine will burn oil.

a flush is not really needed, but I would recommend replacing your radiator cap, this is most often over looked and it is also where most evaperation occurs.

[RipRocK]

Awesome guys! Really appreciate your replies and putting up with these little nit picking questions. I'll keep an eye on the level, but so far, it's remained the same, so no worries. And yeah, I'll go pick a new radiator cap. Cheap insurance.