TINBOAT
01-27-2004, 10:42 AM
Okay...I've been seeing lots of posts about poor fuel economy, and low engine temperatures.
I am a mechanic, and spent a very long time working with imports, quite abit of it was Honda exclusive. Just remember that I'm a mechanic, not a scholar, so please bear with me.
Let's start with the thermostat.
Thermostats are NOT installed in your car just to provide heat in the winter. This VERY important mechanical part is made to maintain your engine at PROPER operating temperature. Virtually ALL cars will not run properly, or efficiently, if the thermostat is not functioning , ie: closed, open, or removed.
If you have cooling issues with your car, DO NOT replace your thermostat with a colder opening unit, if your thermostat is in fine working order, you should look elsewhere to diagnose cooling problems, such as a clogged radiator.
A colder thermostat will cause your engine to think it is still in the 'warm-up' mode, and that mode requires more fuel into the combustion chamber to keep the engine running up to full operating temperature, if you have a cabureted model, and a cold running engine, pop the air cleaner lid off, and have a peek down into the carb, and you'll probably see the choke butterfly 1/2 open. Hence forth, dumping more fuel into the engine.
On fuel injected models, the cooler temperatures are compensated by dumping more fuel into the engine via the sensors that tell the ECM that the engine is still cold.
So what's the big deal about dumping more fuel into a semi warm engine ?
Your engine is made of many different metals (iron block, aluminum head), and these metals expand and contract at different rates at different temperatures.
These expansion rates are figured into the design of the engine, and are set to be optimally efficient at a specified temperature...192/195* on Honda's. (and most other cars today)
Take a look at a piston, get a micrometer, and measure the piston at the skirt, the across the pin boss.
You will find quite a difference in the measurement.
The reason for this, is that pistons are 'cam ground', this is done because the piston expands during warm up, and it is designed to be perfectly round at proper engine operating temperature. (otherwise, the piston would swell up and seize in the cylinder).
During the warm-up phase, your piston rings take up the slack, and will even produde more 'blow-by' with a cold engine.
Now, with the rings supporting a cool running engine, more fuel being dumped into the engine to keep it running, not ALL of that fuel is being burnt off by the ignition system, and guess what happens to all that burnt off fuel ?
...not only will it carbon things up dramatically, it will also wash the thin layer of oil off your cylinder walls, causing premature ring failure, premature cylinder wear, and if run in this condition long enough, it may also thin your oil to the point that camshafts, and main and rod bearings fail. It is also hard on seals and valves...all around not a good thing.
I hope this puts things a little more into perspective as to why I am so adamant about thermostats, and using the PROPER part.
Using a 160* thermostat is not a good thing, not for your engine, not for your wallet, and not for the environment. (try to pass a smog test with a cold engine).
If you have changed your thermostat, and still have cooling issues, it is cheaper to replace a radiator and flush the cooling system, rather than a new engine.
Plus you will save money at the gas pump.
I am a mechanic, and spent a very long time working with imports, quite abit of it was Honda exclusive. Just remember that I'm a mechanic, not a scholar, so please bear with me.
Let's start with the thermostat.
Thermostats are NOT installed in your car just to provide heat in the winter. This VERY important mechanical part is made to maintain your engine at PROPER operating temperature. Virtually ALL cars will not run properly, or efficiently, if the thermostat is not functioning , ie: closed, open, or removed.
If you have cooling issues with your car, DO NOT replace your thermostat with a colder opening unit, if your thermostat is in fine working order, you should look elsewhere to diagnose cooling problems, such as a clogged radiator.
A colder thermostat will cause your engine to think it is still in the 'warm-up' mode, and that mode requires more fuel into the combustion chamber to keep the engine running up to full operating temperature, if you have a cabureted model, and a cold running engine, pop the air cleaner lid off, and have a peek down into the carb, and you'll probably see the choke butterfly 1/2 open. Hence forth, dumping more fuel into the engine.
On fuel injected models, the cooler temperatures are compensated by dumping more fuel into the engine via the sensors that tell the ECM that the engine is still cold.
So what's the big deal about dumping more fuel into a semi warm engine ?
Your engine is made of many different metals (iron block, aluminum head), and these metals expand and contract at different rates at different temperatures.
These expansion rates are figured into the design of the engine, and are set to be optimally efficient at a specified temperature...192/195* on Honda's. (and most other cars today)
Take a look at a piston, get a micrometer, and measure the piston at the skirt, the across the pin boss.
You will find quite a difference in the measurement.
The reason for this, is that pistons are 'cam ground', this is done because the piston expands during warm up, and it is designed to be perfectly round at proper engine operating temperature. (otherwise, the piston would swell up and seize in the cylinder).
During the warm-up phase, your piston rings take up the slack, and will even produde more 'blow-by' with a cold engine.
Now, with the rings supporting a cool running engine, more fuel being dumped into the engine to keep it running, not ALL of that fuel is being burnt off by the ignition system, and guess what happens to all that burnt off fuel ?
...not only will it carbon things up dramatically, it will also wash the thin layer of oil off your cylinder walls, causing premature ring failure, premature cylinder wear, and if run in this condition long enough, it may also thin your oil to the point that camshafts, and main and rod bearings fail. It is also hard on seals and valves...all around not a good thing.
I hope this puts things a little more into perspective as to why I am so adamant about thermostats, and using the PROPER part.
Using a 160* thermostat is not a good thing, not for your engine, not for your wallet, and not for the environment. (try to pass a smog test with a cold engine).
If you have changed your thermostat, and still have cooling issues, it is cheaper to replace a radiator and flush the cooling system, rather than a new engine.
Plus you will save money at the gas pump.