heater blows cold & RPM bounce (2nd Gen 4Runner)
 

1. The heater will blow hot air when the you first turn on the heater. But after a while, its cold. I have replaced my thermastat and coolant. I just don't understand why it gets cold. any ideas.

2. the runner started to an "rpm bounce." I looked in my books and haven't found an answer. it starts to "bounce" when the car warms up, however it comes and goes. some times it does it sometimes it doesn't. On top of that, when I press the brake, the rpm drop and it stills bounces.

:dunno:

thanks for your help!!

re: heater blows cold & RPM bounce (2nd Gen 4Runner)
 

Possible vacuum leak for the brake problem??? For the rpm "bounce," try cleaning your throttle body really well.

I believe the answers to your rpm bounce can be found here bizarre idle On my '91 I owned briefly, I had to cut the wires at the ecu to bypass the brake switch. The idle would fluctuate when I stepped on the brakes, but if I shifted it into 4WD the weird idle would go away...Give it a try.

The thing about your heater....That's so funny because that same '91 4runner I owned did that as well. I couldn't turn the heat on until the engine was fully warmed up or else it would turn cold. If I let the engine warm up, then turn the heat on, it would stay hot. I never got around to fixing that since I had to sell it. Let us know if that link I sent you helped.

Salue

It sounds like you got air in you coolant system and it needs to be bled out. Air in the system will also cause the idle to fluctuate.

How do you bleed the coolant system? Just let the car run with the rad cap off and fill as needed?


thanks for all your help.

you mean that's NOT normal? Mine has ALWAYS done that, I just figured toyota expected me to be tough on cold mornings...that way I could drive around with the windows down when the temp was around 25 and make people give me wierd looks.....lol

Incidentally I have the rpm bounce but if you shift into neutral, it stops and the truck idles higher (obviously.) I attributed it to the 3.slow being 219,000 miles old. And yes, there is a lead on the vacum thingy on the passenger side close to the fire wall. (I had know it leaks, becuase after I turn off the engine, I can hear this faint sucking sound.....(no that's NOT air being sucked into my head! lol)

Ill look and try figure out EXACTLY where it's leaking from...

Yeah, that weird idle I had I thought was a vacuum leak as well. When all the symptoms were the same as that link I provided, I knew it couldn't be just a vacuum leak. When I'd step on the brake, the idle would drop and fluctuate up and down. If I took my foot off the brake, it would stop. It only did it when it was warm also. And, when I would step on the brake and the idle dropped and it started idling funny, I pulled my lever into 4WD and the weird idle disappeared. After doing the mod, I never had that problem again(only had it for a few more months before selling it).

Salue

I installed a keyless remote starter and on cold mornings used it to warm the engine while I got my coffee and got dress for work or play.