Where did my coolant go?
 

I bought my 2004 VR MT last December with 9500 miles on the odometer. Over the last year, I've put about 10,000 miles on the car, mostly stop-and-go city driving.

When July of this year came around, I noticed that funny-looking indicator on the dash representing low coolant would illuminate every once in a while, then go away. I checked the coolant level, and sure enough, it was low. I added fluid to the system to bring it back up to the proper level, and it ended up taking about a 1/2 gallon.

This past weekend, the dash light starts up again, so I checked the level and, yes again, it was low. This time it took 3/8 of a gallon to bring it back up to its proper level. That's almost a gallon of coolant within a year's time!

I haven't noticed any puddles under the car, the carpet on the passenger side isn't wet, and there's been no steam bubbling out under the hood. But I seem to be losing coolant. Is anyone else having to add coolant as if it were engine oil?

that's not good, better take it in and have them check for leaks... hopefully it's just a hose and not a seal in the engine...

you probably did this, but I still have to ask. Check the radiator cap, when the engine is cool of course, and the radiator hoses. You must have a leak somewhere. Also make sure to add some water with your coolant. You don't want all coolant in your radiator and resevoir tank.

Possibly it is only leaking when driving on the road. Look for coolant residue around the hoses and engine housing joints. Also, there have been numerous reports of leaking water pumps, so take a look at the weep hole on the bottom of the water pump to see if you see an residue of coolant there. I would expect there to be residue on the inside of the undercover under the engine as well if the water pump is leaking.

The good news is that if your car does not emit white smoke from the tailpipes, the leak is probably not internal to the engine. But obviously the coolant is going somewhere since evaporation would not account for the quantity you are adding.

Could be as simple as overflow when hot. After 20k miles I wouldn't be too surprised at adding some coolant. I think I had to add some around 28k. But you seem to have a persistent problem. I'd definately have the dealar look it over. Coolant and oil are 2 things you don't want to be losing, particularly on a rotary.

The lack of any visible evidence could possibly mean your engine has an internal problem that is allowing coolant to get into the combustion chamber. It only takes a very small crack or failed gasket to allow the coolant level to go down gradually and without notice; no steam, no puddles. I had this happen to my '91 Explorer and it turned out that one cylinderhead had a very small internal crack that was allowing coolant into one combustion chamber and eventually out the tailpipe. I never saw any steam or puddles, but the coolant level would gradually go down at the rate of about 2 cups per week.

1.3L

My coolant light came on after about 10K also. Very little coolant left. I filled it and took it to the dealer. Thay fixed the hose and a clamp. No problems since,but my engine was flooded this morning. Flatbed to dealer,unflooded and upgraded plugs and battery. I thought I was immune from flooding(no problems for 20K). I've had it all-flooding,recalls,leaking fluids-but,man,do I love this machine and I keep coming back for more

I have had about the same amount of coolant leak out of my car as well. I have yet to spot a puddle. Just last week when the temperature dropped my coolant level light came on and I had to add a fair amount of antifreeze. This week I have been smelling some antifreeze coming through the vents so I guess I should take it to a dealer to see if it all checks out ok.

My engine was replaced due to a coolant leak from the rear rotor housing. It was a Sept 03 build. Make sure they check the engine - probably not what's happening in your case, but better to be safe.

I had to add some to mine around 15k miles when the light came on. No sign of leaks or engine problems either.

mine just starting coming on periodically at 17k, still enough in the resivoir though I havent added any yet. No problems associated with it.

seems like alot of people are having this problem...
My 8 has about almost 21,000 miles on it and no problems with the coolant

and... a question... you should water with ur antifreeze/coolant? how much?
and my friend told me in emergency cases when your car needs coolant u can just add regular water... myth? harmful?

In most cases, the coolant/water ratio should be about 50/50. The reason for that is not just freeze protection, but also to allow for a boiling point of the mix higher than the boiling point of water alone. Of course, in a true emergency where you need to add something to the system in order to continue to drive, water will do just fine. But, when the emergency situation is over, it would be advisable to raise the coolant to water ratio in the system back to 50/50.

If there was a leak on the intake side of the combustion chamber near the intake ports, the chamber wouldn't be at a compression point and wouldn't leak pressurize or raise the temperature of the coolant system as it did when the coolant leaks were in the exhaust side of the engine in the 3rd gen RX-7's. It would put the system under vacuum more often and possibly suck the coolant out and then burn it in the engine. You'd never see it this way. It would just miraculously disappear. The coolant does go somewhere. You just need to figure out where. This would be very hard to diagnose.

thanks for the info.
how often should one add coolant in their car because i havent added anything yet and have seen no need to.

You should only add it if you need to add it. You may lose a few ounces over time due to evaporation, but you should never have to add significant amounts like quarts. If you find yourself adding large amounts of coolant, there is a leak--either external or internal to the engine. Just keep an eye on the coolant overflow bottle and make sure the level is between the Full and Low marks.

Thanks for the replies.

I think I'll let the dealer take a crack at this one.

Just an update.

Took the car in yesterday for the 2 recalls and mentioned the mysterious coolant loss. They called back later in the day to say they wanted to put a pressure test on the cooling system overnight. Just heard from the dealer that a leak was found... in the water pump, similar to a few other posts I've read here on the forum. The good news is they have one on hand. The bad news is they won't have the necessary gasket until Monday.

So, I'm trying to get comfortable in the Pontiac Vibe rental. Gonna be a slow weekend!

Best ratio is actually more around 70/30 (can't remember which is the 70 though). 50/50 does NOT provide the lowest freezing point, but of course the best mix for protection against corrosion may be different yet.

My light has come on recently when I start the car but it goes away before I'm around the closest corner (1/2 block). I should probably check it soon, I'm at 3600 miles.

my coolant was sneaking out of the weep hole. they replaced the water pump. if you guys are seeing this, check the search under "green liquid" for more info. this site diagnosed my problem so I wouldnt have to deal with the service center second guessing me. this happened aroung 20k, and the seals couldnt handle the pressure over time allowing the coolant to sneak out.

Is that right? I've always assumed 50/50. But I don't have to worry about lowest freezing point. Where I live the coldest it ever gets is around 50F. And last night was like 56F.

have someone do a pressure test on the coolant system...

Every 3 months or so my coolant light would come on. I recently pulled off my turbo and found a definite leak at the intake manifold. I vaguelly remember seeing this prior to the turbo, although there wasn't as much of a coolant stain visible. So I don't think this is because of the turbo. Anyone who's losing coolant should definitely go in and get checked.

Now I'm just wondering how much of a problem this will be. I'm not sure if its something that needs to be fixed right away or if I can just deal with the inconvenience of adding coolant from time to time.

Is the picture larger than a thumbnail, I can't seem to make it enlarge.

Pics are fixed now.

Okay guys, about the coolant ratio. The ratio you should use is listed on the back of the bottle depending on average tempurature where you live. The guys in Canada are going to need a different ratio than people in more moderate climates.

Generally, you want to use as much water as allowed. Adding too much antifreeze makes your cooling system less efficient. Water is much better at transferring heat than antifreeze, so the more you have in the system the better off you are. The antifreeze is there to keep the water from boiling/freezing.

Also, when you're mixing your coolant it's best to use deionized water (which you can get as most any auto shop). If you can't get that, use distilled water (like from the grocery store). Only use tap water in emergency situations.

Add me to the list of those needing the water pump replaced. 2004 model, 49K. I've been noticing slow decline in coolant level for the past 6 months. First time, maybe 3 months until next red radiator light, then 1 month, then 1 week. I presume this will happen to more and more 8s as time goes by. I did get it replaced under warranty.

Are there any symptoms to the coolant leaking into the intake or exhaust that is noticable while driving or while the car is running at idle? I have had coolant disappear in the last 7K, I added some water, and now the light is starting to come on again every few drives, but it does go off.

Your coolant is going somewhere. Just because you don't see a puddle under your parked car doesn't mean your coolant is leaking into the combustion chamber. I never saw any indication of a leaking water pump, yet that was the problem. Take the car in and have it diagnosed by a professional.

From what I've read, coolant leaking to the engine will cause white exhaust smoke. What you have described sounds like what is becoming classic RX-8 water pump leaking, if you see no smoke.

Asmoran knows what he's talking about. Very well expressed. The other point about coolant is that it adds some anti-corrosive properties.
Paul.

I've had my car for 1 1/2 and I just noticed that i was running my car with low engine coolant. I checked and there was no leak. I added about half a cup. Anyone had the same issue?

I would think half a cup over a year and a half is probably normal evaporation. Notice that I added half a gallon after 6 months.

Just make sure your coolant loss doesn't increase.

My car is at 7,160 miles now and I've had the car for a year and a month. Just added about 3/4 cup of coolant into the reservoir when I noticed that it was at the low mark. Did not notice any white smoke from the exhaust or coolant puddles on the garage floor.

hmmm, probably should check mine too. I assumed that when I had the Mazda Full Circle inspection a few weeks back they would have noticed any coolant loss. But it wouldn't suprise me at all if they didn't even check it, just checked off the green box on the paperwork.

It is very important to warm your engine well before driving. THe Renesis is made of different metallic structures which expand at different rates. If you rev the engine hard before it has warmed up properly you can get combustion chamber leakage into the water jackets and vice versa, which can cause a coolant loss. Always allow your engine to warm up before driving off, and wait till at full operating temperature before you give it a big rev.

I never rev above 3,500 rpm and shift at around 3,000 rpm during the first 10 minutes after starting the car.

you should have a full collant flush between 30-60k i believe it is i havent worked at a shop since high school so its been about 7 years. that was also piston engines but a good flush never hurts when the same liquid has been sitting in your engine for too long.

they have a machine that would probably work the same for the rotary that it does for all other engines that actually cleans the whole system out and then puts in new anti freeze its great. i also suggest a transmission flush when u do the radiator flush but thats just me =D someone with more experience with rotaries might be able to tell you more correct info as this is my first 1 but i love it sooooo much im glad to join this club and hopefully meet more and more of you in the coming times

Today, a year after my last post in this thread, I had to add about 15 fl. oz. of coolant to the reservoir (coolant level was below the low mark with a cold engine) at 12,420 miles on the odo. Time to take it in to the dealership for a pressure test! For those who has taken their 8 in for a pressure test, how much did it cost?

Mine was having a similar issue - and they completely checked the system - it was fine. Chalk it up to the expansion of the coolant - every car will "vent" some coolant from the expansion tank if it gets hot enough. God knows RX-8s get hot enough!