Over Cooling.. Grr..
Retired Moderator - RIP
Joined: May 2008
Posts: 18,729
Likes: 17
From: NH
Haynes manual and the 2001 FSM from the FAQ/DIY will both give you the test procedure and values for testing all the sensors. If the clutch fan is roaring, then it's bad. Get a new Tstat and test it before installing. Heat can be other issues, but if the motor is only getting to 160 or whatever, need to figure that out first. Like DHV has stated with the temp sensor. I suspect more than one problem. But let's get the motor at operating temp first. So not to confuse the issue.
Veteran
Joined: Mar 2010
Posts: 430
Likes: 0
From: Mississippi
Might check the temp of the hoses entering and exiting the radiator and the hoses entering and exiting the heater core. I'm betting the truck is actually at operating temp, and the stop leak you mentioned in the heater core, along with scale, etc, are not allowing the coolant to flow through the heater core well enough to generate good heat in the cab. Not a lot of markings on the gauges on our trucks, mine reads what i'd guess to be 160-ish if you go by the marks on either side of where the needle sits. 195 t-stat, and truck does not run at 160 though. And the heat works good, had to replace heater core a couple of years ago. I'm not saying run out and buy a heater core, but if it leaked and you put stop leak in it, probably need one anyway. If temperature readings (not gauge readings, but reading with a heat sensing gun, etc.) indicate the truck is really running cooler than normal (180-190), the thermostat is the only thing I can think of that would cause that.
Legend
Joined: Jul 2011
Posts: 8,259
Likes: 4
From: Austin, TX
If there is Stop Leak in the cooling system, I would suspect that the core is plugged to some extend. The obvious hazard with flushing is the leak that casued someone to ut in the Stop Leak will moist likely reappear. But if this is the problem, nothing else will resolve it. So one must be prepared to correct whatever raises its ugly head.
I didnt put the stop leak in there.. I am completely against using the junk.. Its a convenient cover up, but the problems it generates is not good, and you still end up having to fix the original issue.. I found it in the coolant I drained last time I replaced the Tstat.. More than likely the radiator leaks.. I have replaced one for every vehicle I have owned.. its like my curse. I still havent got to test the temp.. Had my sons 6th birthday and easter, so I've been busy.. Ill check out the DIY guide, that will be a major help.. And I also plan on (Plan, hopefully means to get it done.. lol) testing the coolant temps today..
the next low cost moves would be to
interpret the 1300 ohms, there might be a check procedure in the 01 service manual. i have not looked.
temp check the coolant or upper hose with a temp gun.
boil test the t-stat in a pot of water with the wife's cooking thermometer. expected result is that it remains closed up to about 185-190, then cracks open a little, and opens fully at 195.
or blindly replace the temp sensor. iirc they are a bit expensive, seems like $15 or so. i don't want to suggest wasting money.
interpret the 1300 ohms, there might be a check procedure in the 01 service manual. i have not looked.
temp check the coolant or upper hose with a temp gun.
boil test the t-stat in a pot of water with the wife's cooking thermometer. expected result is that it remains closed up to about 185-190, then cracks open a little, and opens fully at 195.
or blindly replace the temp sensor. iirc they are a bit expensive, seems like $15 or so. i don't want to suggest wasting money.
I dont have a problem replacing the sensor anyway.. 211k miles, replacing anything old is not a bad idea..
Rookie
Joined: Jan 2012
Posts: 50
Likes: 0
From: PLaisance Qc, Canada
hi guys, here is my '' two '' cents.
When i bought my Dak, it was in a messy state. There was a cardboard piece in front of the rad, sugesting that the truck was cold in winter.
I checked the temperature on the gauge and it was at 195.
When it started to be cold ( in Quebec it does ) the habitacle was coldy style so i replaced the thermostat for a 195. As with the other guy, the one that was in was also a 195 BUT with streaking marks along the mecanism, so i replaced it anyway.
After, the gauge inside the truck showed me 165 deg. It brought some questions into my mind asking if a did put a GOOD thermostat or got the wrong temp SO i boiled test the new Thermostat with proper figure ( start to open at 190 deg).
I used a digital thermometer and pointed it to the upper rad hose and it was 190deg. after 10 min of idle. I replaced the thermostat sensot with a new one (75$) and now every thing is according to the way it is supposed to be, i can also tell when the thermostat opens because it exceed 200 than it drops to 190...
The sensor was covered with a brownish plaque so i used a wheel buffer and cleaned it completely. I've tested it into my truck and now it Indicates the proper temp ( it too ) now i have a spare one.
One last thing, i will clean the inside radiator this spring ( flush the rad with runing water back AND forth ) to improve the heat transfer from the heater radiator.
If you don't have access to a shop manual i strongly recommend to take a GOOOODDDDD look at the procedure to gain access to this F.?$%*?%( G radiator, you almost have to take the whole dash appart.
Hope this helps<
When i bought my Dak, it was in a messy state. There was a cardboard piece in front of the rad, sugesting that the truck was cold in winter.
I checked the temperature on the gauge and it was at 195.
When it started to be cold ( in Quebec it does ) the habitacle was coldy style so i replaced the thermostat for a 195. As with the other guy, the one that was in was also a 195 BUT with streaking marks along the mecanism, so i replaced it anyway.
After, the gauge inside the truck showed me 165 deg. It brought some questions into my mind asking if a did put a GOOD thermostat or got the wrong temp SO i boiled test the new Thermostat with proper figure ( start to open at 190 deg).
I used a digital thermometer and pointed it to the upper rad hose and it was 190deg. after 10 min of idle. I replaced the thermostat sensot with a new one (75$) and now every thing is according to the way it is supposed to be, i can also tell when the thermostat opens because it exceed 200 than it drops to 190...
The sensor was covered with a brownish plaque so i used a wheel buffer and cleaned it completely. I've tested it into my truck and now it Indicates the proper temp ( it too ) now i have a spare one.
One last thing, i will clean the inside radiator this spring ( flush the rad with runing water back AND forth ) to improve the heat transfer from the heater radiator.
If you don't have access to a shop manual i strongly recommend to take a GOOOODDDDD look at the procedure to gain access to this F.?$%*?%( G radiator, you almost have to take the whole dash appart.
Hope this helps<