wind415

I have a 2004 GX470. Now that the weather has dropped I have noticed that my heater is taking a long time to warm up all it does is blow cold air out of the vent. Subsequently I have started to notice that they car will start to overheat. It will never get to the point where it will hit the red but it will go up and then come back down to mid range. There doesn't seem to be anything else wrong with the car, it idles fine, starts fine etc. Could these two issues be related?

ALAN553

Thermostat?

RCsGX

Have you added / changed the coolant recently?

RickC5

Both: New coolant AND a new thermostat. At least that's where I would start.......

DUKE34

Have the some problem with my 2004 GX. Temp on dash gauge is fluctuating (pretty high and low) and no heat at low rpms rev to 12-1400 RPMS starts kickin heat. Have checked coolant and replaced thermostat (No Fail "great idea") yet still fluctuating. Tore dash apart found servos (not sure which one did what without diagram), but checked wiring connectors and bingo started blowing heat at idle. Put dash back together and guess what, you got it, did it again. I dont know if the two are related. Any good suggestions for us would be greatly appreciated at this end.

DUKE34

I read in another post that our problem is the (SERVO SUB-ASSEMBLY, DAMPER for MODE). This seems to be the servo accessed on the drivers side. One of the symptons of this control going bad is a ticking/knocking noise from the dash as it tries to open the damper, I did hear that on mine. Here is the part number .......... 8710630371. I really don't see how this will fix the temp fluctuating problem, but at least we will be warm when we blow the engine.

DUKE34

OK, the problem we have here is a failure to communicate, after going to order the part at Sewell, it is a dfferent part number and location all together. Hope someone on here can tell us but according to the diagram on Sewells site the MODE servo is the upper servo on the passenger side, part number 8710635120. I hope someone will clarify based on our symptons, the right servo for us. There is only one servo on the drivers side and at least two on the passenger side.

DUKE34

After going through all the possible problems for no heat at idle and fluctuating temp I may have found the simplest of all answers. It is completely shocking to me that a 04 Lexus would not have a low coolant sensor at ALL, which every 2000 or better car I have owned has had and would have apparently saved a lot of trouble. That being said you cannot top off the reservoir and walk away or assume anything, top it off bring the car to temp-let it cool completely and refill, you may have to do this several times to completely refill the system.

ALAN553

if you are down that much coolant, i would be looking for a leak somewhere. these radiators dont have a lot of life to them.

mann777

First sight of cooling issues is start your car have the AC on and in the front of the radiator is the "Sight Glass" check if there are lot of bubbles, This is indication of low Refrigerant, Insufficient vacuum purging or there is lot of Air in the refrigant system. This could be started initially for troubleshooting.

wind415

Thank you for the replies and sorry for the delayed response. I had to leave out of town for a week. I checked the coolant and sure enough it was empty. Although after filling it up I drove it around and checked the level and it was empty again. I then filled it up and then left the car running in my driveway. Withinn a few minutes I had fluid leaking from the from just forward of the passenger side wheel well. Does anyone know where that would be coming from and where to try to access it?

wind415

Correction...the fluid is coming from the rear of the passenger side wheel well.

RickC5

Most likely just some condensation from the air conditioner. Ours drips there after a drive of even moderate duration. Should be plain water--taste it if you're still doubtful. Normal operation.

RXstate

I've got a 2004 GX470 that I've replaced the entire cooling system (radiator, waterpump, hoses, etc) and it's running great. BUT, I can't seem to get heat to my feet inside. I know it's a servo, but I don't know which one or which part number. Anyone know?

RXstate

Ok, I really thought that there must be a problem with the servo on the driver's side of my wife's 2004 GX470. Heck, when it's cold, my feet freeze even when all heat is directed there. Today, though, I climbed in there and noticed that when I changed the direction on the panel from vents to floor, it does indeed change the flow to the floor as its suppose to and the heat does come out there, but it's a disappointing flow rate. The fan is new and works just fine.

The servo on the driver's side appears to be 033700-8870, but I notice this also comes up for GMC. Anyone know if this is the correct part number?