Gary Knox

Anyone here ever replaced the thermostat on the timing chain A8 4.2 engine? I 'think' ours may be stuck open, as it took about 4 miles for the engine to reach operating temperature this morning (29 F ambient).

IF you have, and can give guidance, I'd appreciate it VERY much.

Thanks,

Gary Knox

krazzz

That doesn't seem too out of line for the ambient temperature. Are you used to this kind of temperature or is this new to you? I replaced the thermostat in mine ('04) about a month ago and it takes 4-8 miles to reach full operating temperature this time of year. I don't know of a single V-8 engine that would do it any sooner than that. Now a small displacement 4 cylinder should reach full operating temperature by then but I would not expect a large V8 to do the same. As long as you are at full temp in less than 10 min and your heater is blowing hot air I think your thermostat is working fine.

krazzz

Today it was only 14 degrees here and my car was only at the 1/4 mark on the temp gauge after a 2 min warm up and a 3 mile drive to work.

Gary Knox

That ambient temp was higher than we've had for many days this January (down to 2 degrees one morning). For the previous travel this winter, the temp needle has been off the peg within about 1/4 mile, and has been to full operating temp (needle vertical) within about 1 1/2 miles. Just seemed particularly slow yesterday!

I'll monitor it for a few days before I decide whether a thermostatectomy is required.

Gary-

PaulW

Get a V10.....it takes a while for my car to come up to temperature....usually 5-10 miles on a 15F degree day.

krazzz

Do you park in a garage at night? To get the needle moving in a 1/4 mile is pretty amazing to me. I park outside and while I've never measured the distance before I would say it takes at least a mile to get mine moving and it is never at full temp by the time I reach work 3 miles away. Even in the summer time none of my vehicles have reached full operating temperature by the time I get to work (of course I only drive V8s.) Driving conditions would play a lot into this though. If you have a lot of traffic and stop and go driving you would warm up in much less distance than me. I have only one stop and I the speed limit is 35 the whole way. I'll keep an eye on mine tomorrow and try and get a feel for the time an distance. I will say that I do not think your thermostat is bad if you can get up to temp that quickly. My mother-in-laws thermostat went out on her minivan a month ago and she could drive 15 miles in to our house and it would never reach operating temp.

Mike141

My 05 will take about 7-10 minutes of driving for needle to move in winter. I think your thermostat is fine, that does not seem excessive especially when it's below freezing.

Gary Knox

I do park in the garage overnight. Temperature of the engine/car when leaving is usually in the 40 degree range when outside temp is about 20 F.

Just gonna' monitor for a while. Thanks for the input on you'all's experience.

Gary-

krazzz

I figured you parked in the garage because there is no way your car would heat up that fast if you had it parked outside. I can say for sure that your thermostat is working 100% and you have nothing to worry about.

that_tg

Has anyone done it? I need to change mine. If I can find it on AllData I will share the process.