My thoughts... Cooling is all about flow. It might be a large amount if air in the system. At higher RPM, enough coolant can circulate, but at idle, the top of the engine is running dry. If you have a head gasket problem, it could be burning coolant and forcing combustion gasses into the coolant system.
If the water pump is failing, at low idle RPMs it is not able to push water. At cruising speed, it circulates enough water to get by. I would suspect the vanes have corroded away on the pump impeller. It could be a clogged/blocked radiator. In low rpm conditions, its not able to flow enough coolant or air. Make sure you don't have anything blocking airflow (grille?) and that the fans operate. Possibly the passages are clogged internally. What does the coolant look like? Has this ever been flushed? I have seem all of these cases before... Clearly needs to be addressed asap. Ken Bogart ----------------------------------------------------- 96 Montego Blue FFS Coldside (His) 97 Black & Tan (Hers) 90 Crystal White (sons) ------------------------------------------------------ http://www.miatacare.com http://www.cincimiata.com MiataMail.com list owner On Fri, Jun 8, 2012 at 6:19 AM, Larry Alster <[email protected]> wrote: > First you say you blew the head. How?? Did this problem start right > after the head was replaced. Are your fans running?? Does it happen with > the AC on?? If the fans are running I'd be inclined to think water pump > but the "blew a head" thing still needs an answer.**** > > ** ** > > ** ** > > ** ** > > ** ** > > Larry Alster**** > > ** ** > > 91 Miata White Knight**** > > 92 Miata Silver Bullet (Sold but not forgotten)**** > > 92 Miata Honey B**** > > 04 MSM MX-5 Whooosh**** > > 06 WRX STi Subie**** > > 08 Z06 Corvette (As yet unnamed)**** > > ** ** > > *From:* [email protected] [mailto: > [email protected]] *On Behalf Of *Joey Delgado > *Sent:* Thursday, June 07, 2012 11:37 PM > *To:* [email protected] > *Subject:* Miata thermostat?**** > > ** ** > > Having strange heating issue suddenly. **** > > ** ** > > After long drives on the highway and ONLY when I take my foot off the gas, > the gauge shoots up. So I go on a long drive, pull off the highway and sit > at a light and it starts heading toward the top pretty quickly. Step on > the gas to go at any speed in any gear and it drops back to normal. **** > > ** ** > > Is this a bad thermostat or something else?**** > > ** ** > > Background - This is a 96 Miata. I blew the head and had it replaced by a > friend who's a mechanic. Works pretty fine except the engine is a little > loud and now this heating issue.**** > > ** ** > > Suggestions? Thoughts?**** > > ** ** > > Thanks in advance!**** > > ** ** > > Joey**** > > _______________________________________________ > Miatapower mailing list > [email protected] > http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower > >
_______________________________________________ Miatapower mailing list [email protected] http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower
