1994 Mazda 626 Overheat+no interior heat+erratic idle

1994 MAZDA 626
190,000 MILES • 4 CYL • 2WD • MANUAL
Avatar
NOSHKANOK
  • MEMBER
  • 2 POSTS
My 626 recently began idling up and down between 1500-2000 RPM. As this went on, the temp gauge slowly climbed up near the redzone. I turned the heat on full blast to drain some out of the engine, but it would only work when I was accelerating. Once I limped it home and ran it some more, I noticed water pouring from the right side of the engine. So I replaced the thermostat, water pump, air filter and plugs, and still the car idles crazy and overheats, and blows no heat. As an experiment, I unplugged the MAF sensor at the airbox, and the idle jumped up to about 2000, but stayed steady. When plugged back in, the jumpy idle resumed. I've decided that all I can do now is take it to a shop and ask them to diagnose it. Could it be a vacuum leak, or bad head gasket, or what?[img:19d3da2458]http://www.2carpros.com/forum/automotive_pictures/359818_DSC00174_1.jpg[/img:19d3da2458]
May 23, 2009 at 4:40 PM
Advertisement
Avatar
RASMATAZ
  • CERTIFIED EXPERT
  • 75,992 POSTS
Do you have a check engine light and last major tune up??

Erratic idle could be caused by the idle air control motor/valve ISC or the EGR valve. For the overheating you need to get it block and pressure tested.
May 23, 2009 at 5:28 PM
Avatar
NOSHKANOK
  • MEMBER
  • 2 POSTS
No, no check engine light at all. Very wierd. And as long as I've owned it I've never had a tune up. Tune ups for EFI cars include simple things like filters, plugs, belts. All those are NEW on this car, I replaced them along with the thermostat and w. pump. But IAC and EGR sound like the culprit. If its the compression and I need a new head gasket, then I have a 626 for sale, cheap! :)
May 24, 2009 at 11:43 AM
Advertisement