changing thermostat

victimizati0n · 11-28-2005, 04:12 PM

hey guys.. my dad wants to get a new thermostat because the temp on our impala flucuates too much (like at idle at redlights)

how hard is it to take out? We ere looking for it for a while.. and finally found it... we think.

so where exactly is it.. and how hard is it to replace?

thanks

BNaylor · 11-29-2005, 07:42 AM

Which engine do you have?

harrymay · 11-29-2005, 11:28 AM

if you have a 3.8 this is how

follow the fat hose coming from the top of the radiator,

when it goes into the engine, its right there.

to take it off there are two bolts that hold it in where the "L" adapter is. remove those bolts and it should be right in there.

BTW make sure the car is cold when you do this. otherwise youll end up with coolant running all over the place.

im pretty sure the 3.4 is the same but i dunno

BNaylor · 11-29-2005, 12:14 PM

A pic is word a thousand words. A pic with detailed procedure priceless.
See link below for Series II 3800 thermostat:

http://www.pfyc.com/supportfiles/tstat/tstat.htm

The 3.4L TS changeout is a little different due to access problems. The throttle body is in the way and the exhaust crossover pipe and shield limit movement.

victimizati0n · 11-29-2005, 04:32 PM

i have the 3.4, and it isnt the same as the 3.8

maxwedge · 11-29-2005, 06:10 PM

Quote:

Originally Posted by victimizati0n

i have the 3.4, and it isnt the same as the 3.8

Next time post the engine and save everyone some time!!

BNaylor · 11-29-2005, 06:57 PM

Quote:

Originally Posted by victimizati0n

i have the 3.4, and it isnt the same as the 3.8

Now you tell us.

But that is probably an understatement on the differences. It is a PITA. This is a generalized procedure for a typical GM car with the 3.4L engine and serves as a guide only. How you actually do it is up to you.

************************************************** *

Make sure engine is cold.

Remove battery negative cable.

Drain radiator. Enough to where coolant is below the level of the thermostat housing and out of upper radiator hose.

Remove the air cleaner inlet ducting going to the throttle body. Recommend removing it complete and intact with the MAF sensor. Be sure to disconnect MAF electrical cable. In most applications it may be necessary to remove the complete air box and the throttle body.

There are two small hoses from the heater core return line underneath the throttle body and connected to throttle body that need to be removed. Remove nut holding heater return line bracket from bottom of throtttle body.

Remove coolant reservoir return line located at top of thermostat elbow inlet.

Remove upper radiator hose at thermostat elbow inlet.

The heater core return line (black metal) should be removed to give you needed clearance. The hose retainer can be removed at the side where it goes into the firewall so you can separate the rubber hose from metal line. Also remove two bolts holding fitting at other end at the water pump. Remove spark plug wire guide. Remove heater return line.

If you have a heat shield covering the exhaust crossover pipe then remove it. Total of 4 10mm bolts. Two on each side. Remove heat shield.

This the hard part and takes patience. Remove two 13mm bolts holding thermostat housing inlet at the intake manifold. I used a combination of open end wrenches and 1/4" drive socket (small tools). Remove inlet housing.

Remove and replace thermostat.

Assembly is reverse. You'll need a new thermostat housing gasket.

After assembly refill lost coolant and perform bleeding procedure to get all air out of cooling system.

***********************************************

Good luck and have fun.

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