Thermostat: to drill or not to drill

[wrenchinjoe]

I have an 89 Ranger XLT with the 2.3, and the notorious cold running issue. The temp gauge never gets to the Normal range. I have replaced the temp sending unit (a while ago), water pump, thermostat and hoses (recently while replacing the timing belt & crank seal), and still have the cold running problem.

I have looked carefully and my tstat housing does not appear to have any flat spots or detents that would allow the tstat to "lock" in to place as has been advised.

To eliminate the possibility of air pockets in the cooling system, I have read that drilling a 1/16" hole in the thermostat can help bleed air from the system. I have a new 192* motorcraft tstat and have boiled it to make sure it works.

Question 1: should I drill it? (If this model has an air bypass valve, then a hole is unnecessary, but I don't think it has a bypass.)

Question 2: if so, where? The tstat (RT1140) is pretty small and the gasket takes up the space where you would typically drill such a hole. Is is ok to drill that small hole in the tstat diaphram?

Thanks.

 

[Mark_88]

For the price of a drill bit and all the fuss, I'd go order a t-stat with the jiggle thingy on it and be done with it.

I've never seen them in Canada and have never had a problem with air pockets after a proper burping of the cooling system. My heater runs so hot that I have been warned by the environmentalists (wow, a 17 letter word!) to keep my windows closed in the winter to prevent global warming...a bunch of idiots in snowsuits that think it's too warm already~

 

[wrenchinjoe]

Thanks for the reply Mark. I had a 1/16" drill bit and it was really easy to do. I had read the Motorcraft thermostats are best, and thought I would give it a try. I drilled the hole in the tstat diaphram, as close to the outer edge as I could. When installed, the hole sits at 12:00 in its' housing. Upon restart, burping the air out of the cooling system was foolproof this time

At first, I routed heater hose straight from the tstat housing to the water pump bib for a test, eliminating the heater core and blend door as possibilities for my low temp gauge issue. The temp gauge climbed barely to the N and then fell back down to cold once the tstat opened.

So, while my temp gauge still reads cold, I now have confidence that the coolant actually gets to 192*, that the tstat actually opens when it is supposed to, and that the temp reading is not caused by air pockets. I am thinking at this point the sending unit or gauge itself must be faulty since the heater & heater core were not involved.

 

[Mark_88]

If it's any consolation, my temp gauge reads under all the time. I know it does actually work because when I cooked the head last year the temp gauge was reading way past the normal range. Once I corrected the rad problem the gauge went back to around the C and rarely, even in the hottest weather, goes beyond that level.

Good to hear your drilling worked though...something for others to consider!

 

[matt4068]

So, while my temp gauge still reads cold, I now have confidence that the coolant actually gets to 192*, that the tstat actually opens when it is supposed to, and that the temp reading is not caused by air pockets. I am thinking at this point the sending unit or gauge itself must be faulty since the heater & heater core were not involved.

I know its a different motor, but bear with me.

I put a 1/16" or 1/32" hole in the top of the thermostat on my 5.0 in my bronco, thinking it would help bleed the system.....

coldest rides i've ever had in my life. by temp gauge on the dash, never left the blue section, manual temp sender/gauge I have never went above 95*... It wouldnt even defrost the window. the next day I put a regular 19x* thermostat in. and never turned back. no problems bleeding with either.

 

[snoranger]

I know its a different motor, but bear with me.

I put a 1/16" or 1/32" hole in the top of the thermostat on my 5.0 in my bronco, thinking it would help bleed the system.....

coldest rides i've ever had in my life. by temp gauge on the dash, never left the blue section, manual temp sender/gauge I have never went above 95*... It wouldnt even defrost the window. the next day I put a regular 19x* thermostat in. and never turned back. no problems bleeding with either.

Seems kind of strange that a little hole could do that... Seeing as how there is a 1/2" bypass hose right next to the T-stat.

 

[kimcrwbr1]

You can allways get a temperature gun and measure the temp of the water going to the heater core. Does your heater get nice and hot after about ten minutes running. Take your temp sending unit wire and short it to ground and the temp guage should read hot with the key on. If so the guage is good and if the fuel guage is accurate then the guage cluster voltage regulator is working correct. You should get about 8 pulsing volts to the sending unit with the key on. If it is really cold out try putting a piece of cardboard in front of the radiator to block off air flow and see if that helps?

 

[rosscob]

I've had my '88 2.3 for about 6 months now and it's my everyday driver. I drive about 5 miles to work every day and noticed that the cab never really warmed up. Shortly after I git it the water pump started leaking so I replaced the pump and the thermostat and that seemed to help....for a while. Now by the time I get to work the temp gauge is showing normal, about 1/2 way up but it's still blowing cold air. I can hear the blend door opening and closing so that's not the issue. If I feel the heater hoses both feel warm. I didn't flush the heater core when I replaced the water pump. Could that be an issue?

 

[racsan]

Ive had (3) 2.3 rangers, a ‘88, a ‘92 & a ‘94. only the ‘88 had a great heater, it was also the only one that gave me airlock issues when Id do something to the cooling system. On my ‘94 I made things better by doing a few things, heater hoses covered with foam pipe insulation, fan removed from fan clutch in winter, corregated plastic (political sign) over 1/2 the radiator in winter. Even doing all that it wasn’t truly warm in the cab until you drove over 15-20 miles. They run cool. Ive heard of removing every other impeller blade from the water pump but then youd need a “summer” & “winter” water pump, I wouldnt want to try that one. Oddly enough my ‘88 (with the best heater) was a supercab, my other 2.3’s have been regular cab trucks.

 

[alwaysFlOoReD]

Try flushing the heater core in both directions. If that doesn't help then a new core isn't too expensive and easy to change.