Low Coolant only when cooldown startup

[57chevyragtop]

Update: 6/26/08...Well guys and gals, It has been a few weeks now and I must let you know the the thermostat replacement and good clean out solved my problem on this. Actually the engine is running better and starting easier than when I bought it three years ago. Gas mileage has improved for in town driving from an avg of 17 mpg to 23mpg. Yes it is hard to get to this thermostat, too hard really....but sure made a difference for my engine.

Again I want to thank all of you for your input right or wrong! It's the participation in the forum that counts. You mean well as you post your thoughts and you make this forum work.....kudos!

[57chevyragtop]

Well it's been a few weeks and all is well so far.....Not fully convinced I don't have a LIM gasket problem however. I'll be keeping an eye on the fluid level over next few weeks as I am traveling during that time. I have a gallon of 50/50 mixed going with me but I'll be doing the driving!

[Colt Hero]

Well, it's actually been less than 48 hours since your last post. The leak occurs over several weeks time typically. Then, toward the end, you start losing coolant quicker and quicker.

So - looking ahead to your LIM project - can you do this job yourself, or are you going to pay a mechanic? My Dad just had his Impala done in New England for $528 by an independent. I thought that was a pretty reasonable price. A dealer would've been $1000, most likely...

[57chevyragtop]

the last time I was on today I did not see my previous post for some reason, just wasn't there so I was reposting with added thoughts. I will be doing it myself when the time comes. from what I gather the fluid gets sucked into the lower imtake then out the exhaust after combustion in minute proportions at first then gets heavier and performance becomes affected.

[Blue Bowtie]

Even though the system was apparently "properly bled at bypass and thermostat" you probably did not expel all the air in the system. Even though you used distilled water in at least one of those drain/refill episodes, there is still dissolved oxygen in the water unless you preheated the water to about 180ºF before adding it to the system. Water has an affinity for gasses in air, and will absorb and hold it. Heating that water later (especially under pressure) will liberate gasses and create an air pocket in the system. It may take a couple weeks of heat/cool cycles before the level in the overflow/expansion tank remains constant.

As always, the fluid levels need to be monitored by regular inspection, but the "mysterious loss" of coolant which eventually "fixes itself" is sometimes not really a loss.

Several manufacturers have specifications on the type and quality of water to be used to mix coolant and for top-off. Cummins has/had a very informative section detailing this on their website, and their newer engines are also using an OAT coolant (like DexCool) for the required coolant fill.

[Colt Hero]

I can say that with MY Impala, I never had any performance problems. The car always had plenty of power and never stumbled, stalled, or anything.

However, it DID ultimately make a loud clicking noise ONE day which, as I stated earlier, prompted me to resort to the SeaFoam treatment (which I think did absolutely nothing because the clicking had already stopped the very next day BEFORE I used it).

When I replaced my gaskets, I drew up a pretty nice procedure that I think would allow almost anyone to do the job. I'd say it takes more NERVE than KNOW-HOW to do an intake gasket job on these cars...