| Author | Message | ||
     Chad Meyer (Ccdm3) Member Username: Ccdm3 Post Number: 101 Registered: 07-2002 |
My 98 D1 is overheating at speeds above 50. I can sit it still for hours (or until I run out of gas) with the a/c on and it never gets hot. The minute I hit the interstate the needle runs for the H. WTF is wrong with my truck? | ||
| Jim H. (Victor_mature) Member Username: Victor_mature Post Number: 96 Registered: 02-2003 |
I've heard tell that the temperature gauge sending units are prone to failure and false high readings. When the needle is reading high, shut the vehicle off and turn the key back on. If the gauge suddenly reads normal I'd look at that sending unit. Or, just replace it. DAP sells them for about $8.50 (www.dap-inc.com) -Jim | ||
| Chad Meyer (Ccdm3) Member Username: Ccdm3 Post Number: 102 Registered: 07-2002 |
Yeah...it resets rather quickly. | ||
| Luis Constantin (Luisc) Member Username: Luisc Post Number: 42 Registered: 02-2003 |
If that isn't the problem, then the thermastat is. I fought the problem for months with the dealer, from Dec. to Mar. Then I took matters into my own hands. I started with the least expensive solution, the thermastat, and the overheating at hiway speeds disappeared. Actually, what had happened was, when the dealer was replacing the head gaskets under warranty, during reassembly they put the thermastat in backwards. Since I had bought one and had the housing off, I went ahead and replaced it. But the symtoms would be the same if a thermastat froze shut on you. There is a little safety valve on the side that allows the engine to run cooler at lower rpms. | ||
| Peter Matusov (Pmatusov) Senior Member Username: Pmatusov Post Number: 821 Registered: 09-2002 |
second that. highway driving requires much more power than driving in town or spinning the a/c pump at idle. If you run out of your cooling budget, it starts getting hotter. peter | ||
| Alyssa Brown (Alyssa) Member Username: Alyssa Post Number: 208 Registered: 01-2003 |
Viscous fan clutch? | ||
| Matthew Gibson (Mattgibson) Member Username: Mattgibson Post Number: 47 Registered: 06-2003 |
Just to ask guys, my 96 Diso is overheating going up mountains at 25MPH at night in 72F weather. My fan clutch never seems to get any stiffer even when the engine is very hot. Should the fan completely lock to the shaft when the engine get very hot? How easy should the fan be to turn when its hot? My Disco doesn't ever overheat any other time or at highway speeds. That is what makes me believe it's the fan clutch. | ||
| Jim H. (Victor_mature) Member Username: Victor_mature Post Number: 100 Registered: 02-2003 |
There's much talk about how that viscous coupler is supposed to behave but I've yet to hear the definitive word. Some say it should lock up tight when hot, others say there should only be 'a significant difference' between the resistence between hot and cold. I'm of the opinion that the difference would be slight and that when the viscous coupler fails, it would tend to lock up rather than spin too freely, causing it to roar all the time instead of just a few minutes after start-up. Surely there must be a DiscoWeb member who has purchased a new viscous coupler that could go give that sucker a spin when it's hot and answer this question. (yes, yes, and don't call me Shirley . . .) -Jim | ||
| Luis Constantin (Luisc) Member Username: Luisc Post Number: 43 Registered: 02-2003 |
Chad's problem, though, would not be anything related to the fan. Being that his vehicle is overheating at hiway speeds, he would have a constant airflow threw the radiator. The fan would only come into serious play at slow speeds, like city driving, or after getting off the hiway. The viscous coupler seems to get its temp transfer from the radiator, though. When my thermastat was bad and I had overheating issues, the fan never once pulled air. Soon as I replaced the thermastat, everything went back to normal. Temp, fan action, detonation went away, everything. Mine was doing the exact same thing as Chad's. Overheating on hiway, and temperature goes down as soon as I dropped below 55mph. | ||
| Tony Zuniga (Tony23007) Member Username: Tony23007 Post Number: 117 Registered: 05-2003 |
I am having a very similar problem on my 95 Disco. The temp seems to rise up after 10 minutes of drive time. The funny thing is that if I pull over and shut it off, when I restart the temp goes back down to normal but the car does seem a start a bit harder? I changed my Thermostat today, plus I changed one of my AC Electric fans that was not working properly and cleaned all the grounds that I could possibly find. All of this did not fix the problem the temp still went up high. I am wondering if there is anyway I can test the actual temperature of the car, either with a thermometer or something, anyone have any suggestions?? If the car shows to be overheated but the temp is normal than that would mean in my sending unit right? One thing though when the car shows really high temp I do notice that my AC blows somewhat hotter?? | ||
| Luis Constantin (Luisc) Member Username: Luisc Post Number: 44 Registered: 02-2003 |
Go to an electronics store like Fry's, website http://www.outpost.com They sell those infrared non-contact thermometers that you just point and shoot, and it measures the temp with an infrared beam of light. I'm not sure about how the AC comes into play. Someone else will have to cover that. But it could be the AC that is causing your overheating, Tony. I still say Chad's is the thermostat, though. | ||
| charles pastrano (Charles) Member Username: Charles Post Number: 248 Registered: 08-2002 |
Cooling System: With trucks this old it would be wise to rod and clean or replace your radiator. While you are at it check the hoses, water pump and replace thermostat. Had the same problems redid everything at once problem solved. | ||
| Chad Meyer (Ccdm3) Member Username: Ccdm3 Post Number: 103 Registered: 07-2002 |
I am on my way to LR right now to pick up a new thermostat and temp gauge sending unit. | ||
| ed petrush (Exp) Member Username: Exp Post Number: 56 Registered: 08-2002 |
The viscous fan coupler should spin freely when cold (you should be able to spin it several revolutions when engine is cold) Once the coupler get hot, it will begin to increase its friction and when hot it should not be able to be spun. The heat is transfered from the engine block thru the crank & bolts that attach it to the engine. (not from the radiator as someone else mentioned) I would agree with most people on this board.. I would check the thermostate first, then water pump & viscous coupler. If that doesn't fix it, at least you have done some really good preventitive maintenance (and the cheapest stuff) and then you can think about flushing/replacing the radiator. | ||
| Tony Zuniga (Tony23007) Member Username: Tony23007 Post Number: 121 Registered: 05-2003 |
Ok, I got my hands on a infrared thermostat from my job and tested the engine temperature. After warm up for about 5 minutes the engine temp was at 125 F, once really good warm up, that is driving for about 5 minutes at good speed I checked the temp on the engine block and it read 186 F, I drove it some more until I actually got my gage to read hot, the needle was past the little thermostat picture on the gage, the temp read 194F, I kept taking reading as the needle went up and up it got as hot as 209 F degrees on the engine block. I contacted the dealer and they were not sure about how hot the engine should read with one of these devices but 210 F does not seem that hight to me specially when the Thermostat is supposed to open at 180 F. Does anyone know what kind of temperature the engine should be running at? and also when the temperature read high on the gage my AC cut out, the dealer told me that it was a safety feature to save the compressor. My question here is if the gage is falsely reading high would that tell the computer to shut off the compressor, or is the car really running high therefore cutting the compressor to save it. I am in the process of changing all of these three components, the temp sending unit, the temperature switch, and the fan thermal switch. I don't know if I am needing to have my radiator roded but an answer to both of these questions can save me that pain thought. Thanks | ||
| Luis Constantin (Luisc) Member Username: Luisc Post Number: 45 Registered: 02-2003 |
The problem is that you got one of those issues where the problem can be mimicked by something else. It could be the thermostat, which certainly would be the cheapest and easiest fix to start with. It could be the temp sending unit, which would be the next easiest fix. And so on. When I had this problem, my dealer changed the sending unit, the gauge, everything but the thermostat, all under warranty ofcourse. It wasn't until I decided to deal with it myself that I fixed it. The whole time the radiator never got so hot that you couldn't touch it. As far as my viscous coupling on the fan when my engine got hot, the fan never lock up. It free spun. When I changed the thermostat and the engine got up to normal operating temperature, the viscous coupling would lock up making the fan do it's famous roaring. That's what leads me to believe that the radiator may make up the majority of the heat transfer to the fan through airflow through the hot radiator. The shaft may contribute to heat transfer to the coupler. But if the the air is flowing through a cool radiator because the thermostat is froze shut, the cooler air will cool the viscous coupler. Sounds good anyway. | ||
| Luis Constantin (Luisc) Member Username: Luisc Post Number: 46 Registered: 02-2003 |
Thought this may be of interest on the cooling system. http://auto.howstuffworks.com/framed.htm?parent=cooling-system.htm&url=http://ww w.familycar.com/CoolingSystem.htm I like the part about the fan viscous coupler. | ||
| Chad Meyer (Ccdm3) Member Username: Ccdm3 Post Number: 105 Registered: 07-2002 |
Update...I changed the thermostat and sending unit and flushed the radiator. It is still overheating. Now it overheats when given gas. No gas = no overheat, gas = overheat. Why? The needle on the dash moves as fast as the tach! | ||
| Chris Browne (Chris_browne) Member Username: Chris_browne Post Number: 194 Registered: 02-2003 |
When you drained and refilled the radiator did you run the engine with the top off the expansion tank with the heat on to allow all the air inside to get out? | ||
| Jim H. (Victor_mature) Member Username: Victor_mature Post Number: 110 Registered: 02-2003 |
Gotta be the gauge. I'd go to autozone and buy a cheapo mechanical temp gauge and do a temporary, under the hood hookup and see if that vehicle is getting hot or not. If the gauge is climbing when hitting the gas, and it's climbing as fast as the tach needle moves, it's a gauge/wiring problem. | ||
| Tony Zuniga (Tony23007) Member Username: Tony23007 Post Number: 129 Registered: 05-2003 |
My problem ended up being the sending unit. To anwer my own question, the A/C does get a feed from the ECU as the system thinks is hot it shuts off the compressor therefore killing my A/C. I changed my sending unit and the needle is working like it should. I also changed my switch for the AC fan as it wasn't working properly. Chad make sure you purge the air out of the radiator, I had the same problem your describing when I had not purged all the air out of the system. If you have already done that and the unit is still not working properly check with the local parts store for a infra red thermostat, they are easy to use, buy it, check your system and when done return it. That will for sure tell you if your engine is getting hot or if its your gage or a bad new sending unit. | ||
| Luis Constantin (Luisc) Member Username: Luisc Post Number: 50 Registered: 02-2003 |
Not to be funny or anything like that, because it happens. Is the thermastat installed correctly ? People have been known to install them improperly by accident. Even the LR dealer put my in backwards. Fortunately it was winter and I didn't have a noticable problem until late February. The dealer changed the sending unit and the gauge, neither which solved the problem, and since they had installed the thermostat in December, they ruled it out. It was mid March when I decide to investigate it myself. That's when I found the thermostat in backwards. | ||
| Chad Meyer (Ccdm3) Member Username: Ccdm3 Post Number: 106 Registered: 07-2002 |
I put in a new sending unit and thermostat/gasket but did NOT purge the radiator. I let all of the fluid out at the bottom hose. It pissed out of the engine and the radiator. I then filled it at the resivoir to avoid stripping out that pos plastic radiator fill cap. After reading to purge radiator, I removed the cap. It is now stripped. Like I said POS! When this is all done, remind me to order a metal cap. If I don't run the truck off of a bridge. | ||
| Shaun Power (Shaunp) Member Username: Shaunp Post Number: 74 Registered: 05-2003 |
Tony I don't know why replacing the gauge sender would have any effect on the A/C. The ECU relies on 2 other senders,a water temp and fuel temp sender. The guage unit is totally seperate. The A/C has a HI/LOW pressure switch that will cut the compressor if the gas presure gets to hi or low. Hi gas pressure means it's hot. IF the compressor conitues to run hoses may blow. The ECU will cut the A/C if batery volts are low. The fuel temp sensor is mainly used to avoid flooding at hot start and also gives the ecu a giude to under hood temp. When fitting a thermostat make sure that the little tickle valve is at the top or you may not get all the air out of the system. | ||
| Will Weatherford (Wweatherford) New Member Username: Wweatherford Post Number: 40 Registered: 02-2003 |
If one had a bad head gasket, what would be the signs? Would coolant be lost into the cylinders? I heard that the design of the head gasket and flow path of coolant would result in leakage outside of the block, and not into the head if it were bad... is this true?? | ||
| Chad Meyer (Ccdm3) Member Username: Ccdm3 Post Number: 110 Registered: 07-2002 |
Another update...I have replaced thermostat and sending unit and flushed/purged cooling system. Still overheating. It overheats at highway speeds. It does not under city driving conditions. Last year I had a new viscous unit put on at the dealer. I will be taking it to the dealer in the morning unless someone has a suggestion. Please rescue me from the raping I will receive... | ||
| Luis Constantin (Luisc) Member Username: Luisc Post Number: 55 Registered: 02-2003 |
Funny this topic is still going. I just opened my email and had a message from AtlanticBritish. In the email was a tip on overheating. http://www.atlanticbritish.com/techtips_main.html#EngineOverheat Here's another good one that I have used in the past; http://www.landroverclub.net/Club/HTML/Overheating.htm | ||
| Jim H. (Victor_mature) Member Username: Victor_mature Post Number: 115 Registered: 02-2003 |
Good link Luis, and there lies the elusive answer to the Viscous Coupler question: "Check the operation of the fan viscous coupling. It should not be freewheeling when the engine is hot. It also should not be locked up solid." Jim | ||
| Blake Monchilovich (Azblake) Member Username: Azblake Post Number: 61 Registered: 02-2003 |
I had the exact same problems and after replacing the thermostat and viscous unit, pulled the radiator and had it rodded. Problem solved. The radiator place can flow/pressure test things and should be able to do a recore if rodding doesn't do it. I've (since) heard that viscous failures are when it locks up totally and makes the engine work too hard. The new one moves hot and cold with just a slight difference. | ||
| Charles Allen (Callen229) Member Username: Callen229 Post Number: 51 Registered: 07-2002 |
Hey Chad did this ever get resolved? I am having a similar problem. Mine gets hot going up hills with the A/C running. I have changed the thermostat, had the radiator rodded and its better but still not cured. What did you find out? Thanks Charles |
