| Author | Message | ||
     Fast1075 |
Here's a real stumper. 1999 Ford Ranger, 2.5 four banger, A/C, etc, etc. About a year ago, the thermostat started getting sticky. The temp would get higher than normal before it would level out. During major maintenance (oil change, filters, belt, hoses, cooling system flush), I changed the thermostat for a stock temperature one from Autozone. After that it will not warm up. I had replaced the radiator earlier due to a crack in the plastic tank. If it is cool (Florida cool is anything below 80) it stays dead nuts on cold, even with the ac on. I checked the temperature with a reliable instrument, and it never gets above about 160. So I went to Ford and bought an OEM thermostat. It does the same thing. The only time I can build any sort of heat is on the interstate running 80, and even then it does not come completely up to temp. I took it to a reliable auto shop I have known for years. They changed the T/stat again, same problem. Guy says if I ever figure it out, let him know what was wrong. Summary: (a) Three different T/stats. (b) Radiator was replaced with new. (c) It's not the fan clutch. (d) It's not the temperature sender. (e) It has proper coolant, and is not air locked. I have tried clamping off various small heater hoses, etc in case somehow water is bypassing the thermostat. Cooling systems are simple, this has to be special Ford Tech Members Only double top secret problem. Anyone have any ideas? | ||
| Thumper74 |
Where are you getting that 160 degree reading? If it's anywhere short The thermostat opens at 195? Have you tried actually boiling it in water? a- It's possible, but unlikely that you have three bad thermostats... b- Is it the same thickness/row count? c- Fan clutch shouldn't do much at highway speeds. d- You sure? Measure resistance at a known temp. The boiling water is good for this... Are you getting good heat? Are there two senders? Sometimes there's one for the gauge and one for the PCM. e- You sure? I'd suspect an air pocket that's getting moved at higher rpms. Has anyone vacuumed the cooling system down and refilled? I had one that was driving me nuts, had to take it to a shop that uses a coolant recovery machine under vacuum to make sure there are no voids. | ||
| Ourdee |
If everyone put the valve in the way the guy before them did, maybe it is backwards or the wrong thermostat. Just a guess. | ||
| Thumper74 |
You should be able to read the sensor temp from a basic scan tool as well, that will show you what the PCM is reading, regardless of what the gauge is reading. | ||
| Fast1075 |
Scan tool matches the gauge reading pretty close. I used a K probe inserted in the upper rad hose with my calibrated thermometer. Ohm reading of the temp sensor matches observed temps. Some how or another water is bypassing the t/stat. It is impossible to install the t/stat wrong unless you use a BFH to cram the broken parts in place. The thermostat has a seal around the end where it inserts into the thermostat housing. Unless the housing is somehow warped, allowing bypass, that isn't it either. There is no sign of corrosion in the housing. The cooling system has been carefully maintained. I had a Jeep Cherokee once that the heater didn't work because of trapped air. Had to park it sideways on a hill and loosen a hose to get the air out. This isn't the same sort of problem. But good suggestions, keep em coming. | ||
| Sifo |
There almost has to be something hanging the thermostat open. Has it been replaced with the proper unit? I would make sure there is nothing that can hang it open, housing or gasket. About the ONLY thing that can cause it to not warm up is an open or missing thermostat. Pretty much any other cooling system failure causes overheating. Many thermostats have a bypass hole to allow some coolant to flow even when closed. You could try plugging that hole and see what happens. Somehow coolant if flowing when cold though, that seems obvious. (Message edited by SIFO on March 04, 2016) | ||
| Sifo |
How's the air temp coming out of the heater if you turn it on? If it's getting up to proper temps, the heat should be blasting hot in the summer. It's a crude double check, but simple enough to do. | ||
| Fast1075 |
The air temp from the heater follows the indicated temperature. Run 80 and get the temp to just below mid scale = warm air from heater. Cruising around town, temps on dead cold = ambient air from heater. Guess I will buy a new thermostat housing, and try that. It is a PITA to change. You have to pull the A/C compressor to get to it. | ||
| Sifo |
It's hard to imagine 3 bad thermostats. Not impossible, but it does kind of defy the odds. If you are going through the trouble of swapping it again, you might want to test it before installing it. Suspend it in water with a wire and start heating the water using a good thermometer, blah, blah, blah... Did all the replacements come from the same place? Could be a bad batch sent to the dealer? Try a different source or brand? | ||
| Sifo |
At least here's a good idea to check the operation of the thermostat while it's installed...
source... http://www.topix.com/forum/autos/ford-ranger/TCUG6 V1MFIV03RA98 | ||
| Glitch |
My Ranger had a radiator problem (it was leaking) so I got a new one. I got the same problem, and it turned out that I had an bubble. I filled it up, left the cap off, with a funnel in it's place. Fired it up and let it warm up, once the thermostat opened, and saw it was circulating, I squeezed the upper radiator hose, releasing the bubble. Put on the cap after topping it off, and that was that. Mine was a 4 liter V6 though. | ||
| Ratbuell |
An air bubble would create an OVERheat situation. I've blown enough 2.2 turbo headgaskets to know, an air bubble up against the block side of the thermostat will keep it FROM opening. Does the truck have an electric fan in addition to the clutch fan? My 4.0 Cherokee has one of each. I second the "warm it up with no cap" idea. Every time I service a cooling system, I do that. You won't get a geyser but you can watch the rush of coolant circulation when the thermostat opens. The level will gradually rise as the liquid expands with heat. Let it run as long as you can before it overflows, to make sure everything has circulated as long as possible. Always do this with the heat turned on full-bore so it circulates the heater core as well. | ||
| Hootowl |
The little hole in the thermostat is supposed to prevent that bubble. I would refrain from plugging it up. | ||
| Ratbuell |
I always drill a 1/16" hole in every thermostat I install...for exactly that reason. | ||
| Etennuly |
Heater hoses hooked up backwards? Seen it done. | ||
| Etennuly |
So it was normal before that initial major service work? This is an odd one. Like the Ratman says everything should cause it to run hot instead of cool. I'm still rolling this one around in the ole noggin. Maybe it needed all of those problems to run warmer!  So go out break the radiator tank, loose half the antifreeze, and smack it with a hammer a couple times.....some vehicles just don't do well being treated with respect. | ||
| Ourdee |
Try bypassing the heater? | ||
| Sifo |
While I would expect a bubble to give overheating problems, it's not your friend. It might help to jack up the front as high as you can get it to help purge it out. Some vehicles do have a problem with that. It's cheap and easy enough to try. | ||
| Sagehawk |
Fast1075, I got to get me some of this. I have thought of broaching this subject on badweb before but I thought no one was interested in solving car issues when so many are solving issues on their buells. I bought a 2000 mazda b25 00 in 07 w/ 95000 on it. Next oil change will be at 250000. I have fought this issue for the whole time. Truck never codes as being cold. I have replaced radiator due to leaks. Fan and clutch are gone. 14" hayden fan is in its place with a manual switch to turn it on. I hardly ever use the fan. Oe thermostat is in now. Bosch code reader live data shows 183/178° at 75 mph on frwy. I drive 500 miles a week to work. Have stopped on side of frwy halfway home and shot with a laser thermometer top hose and plastic thermostat housing 160 or so. The are 2 sending units in housing. Both have been checked and replaced. Gage at this temp shows less that sweeping band on gage. Also slow down and motor cools down. Yes, 195 thermostat and I check every one with thermometer up to boiling water. Watch it cycle as well. Bear with me for a moment. I've surmised bout every scenario possible. Best conclusion; truck body design, motor all cast iron, plastic thermostat housing that has sensors in it, (not in head so much) that air flow and motor being heat sink actually the motor gets rid of heat effeciently without so much liquid cooling. Went and checked value in bluebook once and discovered truck only was rated at 119 hp. Like old 40 hp vws, you couldn't hardly kill a vw bottom end at 40 hp rating. Is it possible that an engineer actually got all the mechanicals designed 'correctly'. Yeah , I've run cardboard in front and you can make it run warmer but when you want ac then you need the extra airflow. What a deal. | ||
| Ducley |
I had a 95 Grand Am that had a vent at the highest place on the engine(directly above the water pump) following a few pipes that bled locations that would trap air. Just had to crack the microbolt(?) open till all the air was out then close. The Ranger doesn't have anything like that? | ||
| Sagehawk |
Etennuly: had to ask bout hooking heater hoses backwards. Would this be at engine or at heater core? I have had to replace heater core sometime back but hose were put back as they come off. Not saying they were right to start with. I've tried to find schematics of cooling system to see if all my hoses were right or not. Haven't come up with that yet. Also slow warmup kills me getting out of town in mornings. Truck acts like it comes off cold start enrichment to quick and idle quality sucks mostly. It dies at least once at about the same stop sign every morning. It does get better when hotter. Problems are a lot less in texas summers. A big thanks to all who want to think this over in their spare time. I do all this while listening to stingrays, aces, bruins , and swamp rabbit hockey games. | ||
| Sagehawk |
The 2.5 four banger doesn't have anything like that. I have a fair incline at end of drive to street junction that I back truck into. It's a fair angle that front is considerably higher than back . Best way I have of getting air out. Drive a short distance and repark. Open cap and level has fallen and fill a bit more. 2 or 3 t I me of this and I feel good as then level doesn't fall and overflow jug level takes it from there | ||
| Fast1075 |
Think I have it figured out. The housing is composite. It has a built in bypass for the sensors (one for the gauge, one for the ECM) The thermostat goes into the housing nose first (it is impossible to install backwards). Of the two I replaced, it took "two thumb" pressure to seat it in the housing. Didn't think much about it at the time. I have no idea if the bypass has a check valve or anything that may be stuck open allowing too much coolant to bypass, and I won't until I install the new housing and autopsy the old one. Back to my idea of what is wrong. I think the bore in the housing has gone out of round and is binding the thermostat, which is a bit flimsy to begin with. Driving it yesterday, it actually came to temp once, then went back to dead cold again. The thermostat must be sticking. The new thermostat that replaced the last one that was doing the same thing. I ordered a new OEM Ford housing assembly which includes the housing, thermostat, and sensors. I will let you know how it turns out. | ||
| Hybridmomentspass |
Neat thread, and cool to see so many working on this. Had a ford product years ago (Mercury) that had similar problems, but it was due to a switch failing and running the fan constantly, would take a very long time to get warmed up/never warm up completely in cool/cold weather Best of luck Fast, hope these new parts solve your problems | ||
| Etennuly |
The heater hoses are actually different sizes, but that does not preclude the home mechanic from finding a way to force one on and crush the other. Then they wonder why the heater system did not work right and the engine no longer came up to temperature as it should. The system on that car made it act like a bypass from the intake to the water pump. I can't recall what kind of car it was on from being such a long time ago. It was one of those early 80's heavily gooked emisssions equipment cars with a complicated coolant flow system with something like four coolant ports other than the main radiator hoses. | ||
| Hootowl |
If the radiator cap is not the highest point in the cooling system, it's not where you purge air. Most new car radiators are slung pretty low. I would check for the aforementioned bleed screw somewhere near the thermostat housing. | ||
| Sifo |
If the radiator cap is not the highest point in the cooling system, it's not where you purge air. Most new car radiators are slung pretty low. I would check for the aforementioned bleed screw somewhere near the thermostat housing. Many depend on "burping" the hoses. My Miata is like that. Both my Triumph bikes were like that. It seems to be a problem that even the dealer's techs don't manage to get done satisfactorily. I've always heard of the problem causing high and or inconstant temps though. Sounds like he may be on the right track. Having to force it into the housing could easily cause it to bind and not close. Depending on how cheap you are, you could just "fit" it with a file. | ||
| Natexlh1000 |
My dad told me that the Renault LeCars has to be hoisted up at a 30 degree angle to get the bubble out if you ever had to open the cooling system. He said no matter what you did, it would never purge itself out until it was done like that. | ||
| Sagehawk |
Fast1075, if you would throw a part number and cost that you incurred on those parts my way. I would appreciate it. I've not noticed two thumb pressure putting thermostat into housing yet. I coat the rubber gasket mount with Napa sylglide to lube it up. Also that rubber gasket was gone off of the first thermostat that I ever changed out but since they haven't stayed in long enough since, I didn't think that was part of problem since the first one. I'm gonna try to find a schematic of water pump hose routing this week to understand better the flow of the system. Take care and best wishes! | ||
| Sagehawk |
Pix of thermostat in question.  |
