Overheats

[saabfan9]

hey guys while driving with air flow everything is cool but if I get stuck at a light the temp climbs I hear the fan kick on but still climbs. I've heard you guys talk about an electric water pump can you share a link where I can find one

[squaab99t]

hey guys while driving with air flow everything is cool but if I get stuck at a light the temp climbs I hear the fan kick on but still climbs. I've heard you guys talk about an electric water pump can you share a link where I can find one

Stock setup should work fine. Try this test. While at idle, get the fan to cycle and put a sheet of paper on the grill to be sure the fan is pulling in air and not pushing.

[gmreider]

Also use the 82 degree C thermostat and the 82 degree C fan switch on the radiator. what year is the car? Later 900 's had some wiring were only one fan runs unless the A/C is on. 91 up 2.1 s models for sure. They can be rewired for 2 fan operation easily.

[saabfan9]

sorry guys I forgot....1973 99 ems 2.0 stock

[sjones]

I had the same problems early on ..
I put a lot of effort into my 77 99 to get it to run 'cool' and ended up taking apart the electrolux fan, cleaning it and lubricating the bearings. I also replaced the switch on the radiator as well as the thermostat .. and check those regularly. Check to see if you have a service recall that installs a collar at the intake near the throttling housing. This was was to keep the throttle from freezing due to cold weather but more than likely that collar is full of debris and isn't passing coolant anyway. I removed that from mine.
I also had my radiator and heater cores flushed and pressure tested. The heater core is a real pain to get out .. but I was doing a lot of work in the interior and engine bay and could take care of that then.

Now my needle stays in 'normal' and if it ever creeps up (like at a light) it will balance itself out when the fan kicks.

[99Super]

On those early-style radiator fan switches (then ones mounted in the outlet pipe),there is a small disc, about 4mm, that can be removed and the rheostat can be adjusted with a small screwdriver. I don't think those early units are easily available any more even if there were a cooler option.

John

[rsp57]

Check the water temp with a thermometer, 99's always read 3/4 on the gauge

[Crazyswede]

Check the water temp with a thermometer, 99's always read 3/4 on the gauge

My 99 always read in the middle. I was running an electric water pump, a new radiator, and a good thermostat. If the temperature climbed up to 3/4 it was because the thermostat was getting old and was sticking.

[Chouan]

On hot days my 99t will read 3/4 of the gauge, but generally I get right through the N.

[DougM]

Mine stays cool if I'm moving, but if not moving for an extended period of time, the temperature creeps up. New radiator installed in 2002 during the restoration. I could never rely on the fan to kick on, so I wired in an extra switch to turn the fan on whenever I want.

[Crazyswede]

I had a lot of cooling issues with my first 99 and also had a manual cooling fan switch. My later 78 5 door 99 with the electric water pump never had any cooling issues. I don't know if the mechanical pump doesn't flow an adequate amount at idle or if it becomes a combination of old worn out radiator etc.

[squaab99t]

Did you conduct the fan flow direction test? I ask because my wiring was swapped at one time and cooling was a problem.

[Chouan]

I had a lot of cooling issues with my first 99 and also had a manual cooling fan switch. My later 78 5 door 99 with the electric water pump never had any cooling issues. I don't know if the mechanical pump doesn't flow an adequate amount at idle or if it becomes a combination of old worn out radiator etc.

This is a good theroy, possibly supported by the change in number of vanes through the years.

Also, I think it's location location location. From Triumph Stag An Enthusiasts guide:

[Chouan]

I keep my coolant reservoir "over" filled.

[99Super]

I keep my coolant reservoir "over" filled.

Yup.
I keep mine nearly full as well. I have a small overflow tank (a bicycle water bottle and cage) and a M-B radiator cap.
If the water level gets low in these cars, the pump will pull air in from the expansion tank and cavitate the pump. Especially at higher revs.

John