[BlackRat]

I am pulling my hair out over this. The car can sit and idle in the driveway for 20 minutes and never get higher than 180*. I can then take it out on a long drive and still never gets over 180*. But if I allow it to get to 180* and then shut the car off which naturally causes a spike in temp usually to about 210 the cooling system will not recover once I crank it up again. After cranking it up again and taking it down the road it will maintain the 210 but if I get into traffic or have to stop at a light it will spike again as high as 250 and will barely go down from there. I am running a Dewitt's BB aluminum radiator with dual spal's set at 160* for low and 190* for high. Fluid is 70/30 water to antifreeze with a bottle of water wetter. Stat has been changed twice now running a Mr Gasket HP stat which I tested before I installed it. Ignition is @ 18* adv at idle and 36* all in @ 3000. Carb is set pretty close and may even be a littl on the rich side still. I have been told that the Victor series H2O pumps need higher rpms to ncrease flow. Is it possible that the pump is not flowing enough at the low rpms?

Wade

 

[SIXFOOTER]

Where is the temp sensor for your fans? Are the fans cycling?
It sounds like there may be air getting in the system, do you have a vent hole drilled in the t-stat? Are you getting bubbles in the radiator?

 

[BlackRat]

Fans are cycling. The temp sensor for the fans is in the intake mainfold at the port near the distributor. Have not noticed bubles in the radiator but have not really looked. But why can it maintain the correct temp from start up to shut down but then cannot recover to that same temp when cranked back up again?

Should I move the sender from the intake to the passenger side head? I have the sender for the guage in the drivers side head and that is what I used to program the fans so it seems like the guage and the temp sender for the fan controller are in sync.

 

[Elduderino]

You have verified, or are confident that the temp sender and gauge are working properly? Whats in the drivers side head, a plug? Why not use that side for temp and pass side for fan, Just curious? When at 210 or 250 your fans are running? Overflow bottle full, empty, bubbling? Lower rad hose colapsed at high temp? Can you hose off rad while ideling and see temp coming down? Proper cap pressure rating? Running A/C?

I really dont think timing or mixture is your problem, or you would experience that at all times, not just at re-start.

Really strange, its prolly something simple.

 

[69 DIRTY RAT]

BlackRat I've had a similar problem lately too! I have an edelbrock highflow pump, a 'be cool' alum. rad. and a spal twin fan. One day my temp was running almost too cool then the next day I was in a wedding convoy and the temp shot up and boiled over! and has never been the same?
I found out that I also had Cavitation (bubbles) in the fluid? We built a tank with new cap above the thermostat housing to rid any air pockets,closed the radiator opening (welded sheet over it), checked the radiator(flows fine!), did an CO2 dye test in the radiator (in case of blown gasket), have new hoses (& checked them- fine). Put in some PURPLE "ICE". It runs cooler but still heats up to 210 in traffic! Temp sender is on the manifold.
I'm not sure if its my imagination but my 'Spal' fans dont seem to be pulling as hard as they used too? So I've bought a 95 Lincoln Mark8 fan (most powerful fan made for a passenger car, up to 4800cfm!) to be retro fitted. The only thing I havent checked yet is the pump! So I'll be pulling that out soon in case something has happened to the blades inside? or maybe just get a new electric pump?

Sorry I'm not trying to steal your thread, I just know how you feel! Good Luck! If I find the problem I'll tell you!

 

[mrvette]

Methinks the rad cap is not worth a flip in either case....and you all better check the hoses for slow/weeping...every once in a while my vette pisses a bit of coolent on the ground...green....and I just look and wonder as the rad is never LO....go figger....

cat marking it's spot??? Dawg??

grrrrrrrrr.......

 

[rjent]

I believe guys you may have an air bubble in the system somewhere. It has been a while but I seem to remember a bubble getting in the heater core area and being a cronic problem until I bled it all out.

Something to think about! :thumbsup:

 

[69 DIRTY RAT]

I'm sure its been bled, I did that when I put the radiator tank above the thermostat area? Anyway I'll look at that again, maybe I didnt do it good enough?????, thanks
There is no leaks in any of the hoses or fittings anywhere, and I have the right cap.