Question-------------------------
Followup To
Question -
I have a 1997 328i, with inline 6 cylinder engine, with 89,000 miles. The thermostat gauge near the spedometer has started to lean more toward the cold blue section. For the past two years it has remained exactly in the middle. Now it is leaning still within the normal range but exactly on the far left line toward the cold indicator. if i keep the car in park and step on the gas, i can get the needle back to the exact middle normal position but when i start driving the needle will lean towards the cold side. what could be causing the engine to run colder?
Answer -
Frank,
You are in luck!!! I own a '99 328is, and I had this problem as well... until today! I'm not sure why, but my car, a friends 94 325is and M3 all showed these same symptoms at the same time. a quick fix helped them all! I live in Georgia and we have just recently started getting cold weather.
I dont know if you are mechanically inclined, so if you know the following please disregard.
Most cars have a cooling system that runs coolant through the engine, and back to the radiator to remove the heat, then the cycle starts all over again. In this system there is a Thermostat. This is basically a door that blocks coolant from entering the engine, until the car is up to temperature. Why would you need to cool a cold engine, right? This Thermostat works via a spring that loosens as the coolant get warmer. As the coolant gets up to about 92° the Thermostat opens slightly and allows colder coolant to enter the engine. If the engine gets too cold, then the door will close some and regulate the ammout of coolant.
Well this "door" gets thousands of heat-cycles in its lifetime, and like bending a paperclip back and fourth, it finally breaks.
If you can do it yourself you will save a ton of money, and it's not that hard.
Local parts stores sell the thermostats for ~$50.00, but you can get what the dealerships use from www.bavauto.com, for $25.00, and it comes will the seals that are necessary (that's what I used).
What's happened to your car is that the door is stuck open, and the coolant cannot be regulated, and the engine runs too cold. Engines need to be warm so all internal components are expanded to operational sizes, and combustion takes place properly.
If you are interested in a write up of how to change this thermostat I would happily oblige you, but let me know.
Take care Frank!
Josh
Josh,
Thank you so much for your answer. I had a feeling it might be the thermostat. I am definately interested in a write up about how to change the thermostat. It sounds relatively easy and something I would want to try. I look forward to your write up.
Thank you
Frank
AnswerFrank,
If you have a decent set of tools you will have no problem changing the thermostat. You will need:
1- Large wrench (probably 1-1/8")
1- set of metric sockets (you will only need 10mm, 12mm, 13mm, 14mm.)
1- (4"-6") extension for sockets
1- Large Flat-head screwdriver
1- small Flat-head screwdriver
1- bucket or pan that will hold 1 gallon of coolant
1- thermostat and rubber gaskets. (www.bavauto.com)
first thing to do is to get the car slightly elevated. I have a Jack and Jackstands, but for this job only need about 3-4", so you can drive the car onto a 2x4 so you will have enought room to drain some coolant out.
You dont "HAVE" to elevate the car, you can just pop off one of the hoses, but it's a little more messy.
Either way, place the catch pan beneath the car, and remove the radiator cap (on radiator). Go below and on the driver's there is a blue (on most cars) plug on the bottom of the radiator. Take the large screwdriver and remove this plug. Coolant will come out, about a gallon of it.
Now move to the front of the car, and look down behind the fan. You will see a large nut on the back of the fan. This is connected to the water pump pulley, and can be a pain to get off. IT IS LEFT-HAND thread, so you will have to turn it CLOCKWISE to loosen it. Take the "big wrench" we talked about and try to loosen it. You might have to take a hammer and tap on it to "jolt" it loose. Once you have it loose, just spin if off the pulley, and pull it up and out of the way. It's a good time to test the fan clutch, so grab that big nut and try to twist it. If there is little or resistance, you should replace this too.
The worst is over, now look down to the front of the engine. You will see a rubber hose running into a black plastic housing, then another rubber hose running out the opposite end. The thermostat is behind this black housing. take the smaller screwdriver and remove the clamps on the rubber hoses on both ends, and remove the hoses. There are 5 bolts holding the housing on 3 of them are 10mm, and one is 14mm (some cars may differ). Remove all of these and the housing will slide off. Once you remove this housing, you will probably see the thermostat hanging out of the front of the engine. Take note of the how it is positioned in the engine. IT WILL HAVE TO GO BACK IN THE SAME POSITION! Pull the thermostat out. Make sure there are no peices left inside the engine. Once removed, clean the area where the thermostat was, with a scotchbrite pad. Take the black plastic housing, remove any old seals that may be intact, and scrub the flat surface to make sure it's clean and will seal correctly. Once cleaned, replace the orange gasket in the housing. Take the new thermostat and install it in the engine with the seal on it. Now take the black cover and reinstall it. When you retighten those bolts, make sure not to strip them. They will strip out easily, as they are aluminum, so take caution. reassemble in reverse order. When you get to the fan, just get the big nut started (remember it's left-hand threaded). When you crank the engine it will tighten it's self, so you wont have to worry about trying to tighten it.
Once you have everything buttoned up, make sure the plug is installed in the bottom of the radiator, then poor coolant in. There is a black screw beside the coolant cap, loosen this to let air escape. Start the car and watch the bubbles come out. Make sure your heat is on inside the car, so it will flush any bubbles out from inside as well. you may have to refill the coolant as some will run out while the bubbles are escaping. Keep doing this until the bubbles stop, or are very few. Retighten the bubble screw, then replace the coolant cap, and you're done!
It takes me about 30 minutes to do all of this, and it beats paying $100/hr at the dealership.
Good luck, if any of this is unclear dont hesitate to write back!
Josh
