A question about coolant reservoir level REVISTED

[dirty hippie]

I check my oil and coolant level at least once a month, usually after a fill-up.

Levels are checked always when engine is cold, usually in the morning, but sometimes on a hot afternoon--but ALWAYS before driving.

Well, in regards to the coolant level in the reservoir tank, I was wondering what is considered normal/accepatable in level drop.

Here's the low down. From Sept. 2010 to Aug. 2011 (my most recent level check, which was today), the coolant level has dropped approximately 1/2 inch from the MAX line. Wait, you're thinking, that's nothing since almost a year has passed. But the thing is that I've only logged in around 4,000 miles in that time period. I don't drive that much and ride my bike when I can. Also have another car, but that's rarely driven, as the Insight is my primary car.

So 4k miles and 1/2" drop in coolant level in the reservoir? Is this accepatable? I don't race the car or rev it. I have a Scangauge II and water temp normally registers at 193-195 when it's fully warmed up, though during coasting or fuel-cutoff mode temp can drop to 188 and can rise to 197 when using AC or when car is going slow in a parking lot.

Btw, I'm just reading the level on the reservoir and NOT removing the radiator cap.

For those who check their coolant level often, how much is the drop in your Insight?

[Eli]

As long as you don't have oil in the coolant or coolant in your oil and the engine's temperature stays consistent, I wouldn't worry at all.

I think I look at my coolant level about once a year.. it does slowly drop..It's gone from the high to the low mark in about 3 years, and 72,000 hard miles.

I really need to do a coolant flush/fill, actually.

[dirty hippie]

I'm thinking the level drop may be due to evaporation at the reservoir. But I think that's quite a bit of evaporating! Many months back when I first got the car, I discovered a pinhole leak on one of the small heater hose (located under the air intake). The level drop in the reservoir was very obvious, as it would drop a few mm each day I checked--all from a tiny pinhole leak. When cold, the hole would be "sealed" by a green drop of coolant, which I soon discovered and thus replaced the hose. My measurement of the level drop began after I replaced this hose and bled the cooling system.

I don't think I have genuine Honda coolant. When I changed the hose I lost some coolant and added Prestone coolant that is labeled for ANY CAR and ANY COLOR. I read somewhere that Prstone coolant evaporates more easily.

Eli, your level drop sounds insignificant compared to mine, considering that the years and mileage is mucg greater vs my 11 months and 4k miles.

[gilbertguy]

All vehicles will lose coolant over time, the reservoir on the Insight is very very tiny compared to other cars so even a small amount of loss stands out. I would keep your eye on it and check it often, you may have a very tiny leak some where that isn't noticable but over time shows on the small reservoir.

Bottom line keep your eye on it but until it gets to the point you can see it leaking, see oil in the coolent or coolent in the oil I wouldn't worry about it to much.

[dirty hippie]

See, that's what concerns me from time to time. If this drop in level isn't the normal average for the miles driven or time passed, then something is not right. I've always kept an eye on the coolant level since getting the car. Shortly after buying it, I learned it had a bad head gasket. PO changed it and had the head milled. Overall, I think the HG leak wasn't a big one, as I didn't notice any cross contamination between oil and coolant, no white smoke, no CEL light, no overheat, spark plugs didn't look like they were steam cleaned or had coolant deposits when I replaced them, and the PO said the head surface was within spec when he took it to a shop but had it remilled anyway for good measure. Anyway, that's done and over with.

If there is a leak somewhere, and say coolant is getting into oil, then for the most part I won't be able to tell if there is water in the oil since the loss is very slow (assuming there is a leak). It seems like every month I check the level I notice a mm drop. After about 11 months and 4k miles, level has dropped 1/2" from MAX line. Surely this can't be normal!

As mentioned earlier, SG2 reads at 193-195F and temp gauge reads at 6 bars max. I'm not smelling coolant and don't see any visible leaks whatsoever. All this sounds normal and I shouldn't worry, but it seems that others are not seeing such a drop in coolant level in relation to miles driven. I understand that over time coolant will evaporate from the cooling system, but usually the loss comes after many miles and years, from what I've read in different car forums. Anyone here seeing the same level drop and can confirm that my level drop is normal or not?

[Varak]

I've seen the same level drop over time, but not miles (I drive 50K+/year)

I've driven my car for 3 summers, and every summer I lose about half an inch to an inch.

The actual amount lost is extremely small, as in a few ounces at most.

I recently changed my coolant after 100K hard miles and it still looked like new.

[dirty hippie]

Originally Posted by Varak

I've seen the same level drop over time, but not miles (I drive 50K+/year)

I've driven my car for 3 summers, and every summer I lose about half an inch to an inch.

The actual amount lost is extremely small, as in a few ounces at most.

I recently changed my coolant after 100K hard miles and it still looked like new.

Varak, by "every summer," do you mean that you lose that much coolant in the span of 3-4 months or in a span of a year?

Btw, just to clarify my coolant loss...the 1/2" drop is from the MAX line and not 1/2 way between the MAX and MIN mark. Still, you guys think 1/2" in drop in $4k miles is a tad abnormal?

[Willie Williford]

I'ts not actually the "miles" I would take into consideration, I would be more concerned about the number of "cycles" between hot and cold temperatures in the radiator.

HTh
Willie

[gilbertguy]

Yes it does sound a bit suspicious but the problem is unless you can either see an external leak or find coolant/oil mixing there isn't a whole lot of options left. You can take it to a professional mechanic and they have an instrument that can test for a head gasket leak.
Head Gasket or Combustion Leak Test Procedure (Gasoline Engines Only)
Basically they are testing to see if there is exhaust gases in your coolant.

Keep us informed on what you find.

[dirty hippie]

Willie, the 4k miles were accumulated in the course of 11 months from commuting to work (20 miles round trip) and going to places, with my longest trip being about 50 miles. So there are a lot of cold/hot cycles.

I remember very early on when I started checking the coolant level, I'd sometimes notice a faint coolant smell emanting from the driverside headlight, right where the reservoir is, after a drive. Some days I didn't notice but other times after a drive I could smell it if I sniffed that area. Didn't see any wet areas on the reservoir. Some head scratching. Then I decided to check if the cap was screwed on tight. I was able to tighten it about a 1/4" more. That fixed the coolant smell. My guess was that the cap wasn't on tight enough that coolant evaporated out and hence the smell. No more coolant smell. I'm wondering if I'm losing coolant there through evaporation. If you ever look at the reservoir neck, there are two "weep" holes. What is their purpose? I'm thinking if I should check for tightness of the cap again. I don't think it's gotten loose but rather that I was afraif to overtighten the last time, so I didn't use gorilla strength in turning the cap.

I wonder if I should do the cheap HG test by removing the radiator cap and starting the engine to see if bubbles come up. If combustion gas is getting into the cooling system, wouldn't I see bubbles in the reservoir or even coolant that has been pushed out?

Car drives fine with no temp spikes. The oil is amber in color (though with such a relatively small loss, I wonder if coolant would even show up in the oil) and I've cautiously sniffed the exhaust. Nada. Is this much ado about nothing?