The never-ending overheating story... 1998 Disco {Please Help!}
#11
07-03-2013, 07:01 AM
Rock Crawling
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I would just add to Savannah's comment about the clutch fan, mine seized up (no spin) and I drove it for a while like that with no problem, except the warning roar that let people know I was coming. It is worth replacing though, it's much more fun driving with a functional clutch fan. My bet is on the radiator. The aluminum ones aren't bad. But I would also urge you to get an UltraGauge so you can be sure what is going on with the temperature.
#12
07-03-2013, 08:12 AM
5th Gear
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I have had same problem with my 1998 LE thus far I have done cooling system flush replaced all my hoses (leaks) replaced pressure cap fan clutch is good. yesterday replaced stat with 180 and mechanic is telling me both condenser fans are bad. so i am shopping those got one used from paul fair price. the other one i am rebuilding with the 1996 denso motor new used in the toyota corrola fits perfect(same motor $45) better than $392 from parts store. I am replacing those this weekend coming up i'll let everyone know. i run a Ultragauge on it and set alarms at 225 I see 196-200 on highway and bumps to 221-230 if sitting in traffic or short run.
I guess next step may be a recore.
I guess next step may be a recore.
#13
07-03-2013, 05:19 PM
Pro Wrench
I listened to these guys about getting an Ultra Gauge.
I am so THANKFUL that I did.
The reservoir bottle plastic line broke off while my wife was driving, the line that goes to the throttle heater, and the coolant emptied.
The Ultra gauge alarm went off at 240 and she immediately pulled over. The gauge on the dash still was pointed in the middle.
Shut it off, filled the bottle, drove it home...
Next day I priced a bottle from LR and was told $264 for the bottle and $64 for the plastic line.
Went to Harry's U Pull it, found a practically new one for $7.
My next job is to replace the TSTAT with a 180.
But I am doing the head gaskets in the morning, so I have to find all that data.
I am so THANKFUL that I did.
The reservoir bottle plastic line broke off while my wife was driving, the line that goes to the throttle heater, and the coolant emptied.
The Ultra gauge alarm went off at 240 and she immediately pulled over. The gauge on the dash still was pointed in the middle.
Shut it off, filled the bottle, drove it home...
Next day I priced a bottle from LR and was told $264 for the bottle and $64 for the plastic line.
Went to Harry's U Pull it, found a practically new one for $7.
My next job is to replace the TSTAT with a 180.
But I am doing the head gaskets in the morning, so I have to find all that data.
#14
07-04-2013, 12:07 AM
Three Wheeling
Join Date: May 2010
Location: St-Pacome, Quebec
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No replacement was planned since i run the ac only occasionally.but if a corolla one fits, i might try that....from what year is it?
#15
07-04-2013, 12:17 AM
Super Moderator
Easy to test D1 aux fans, they should come on with AC. They should suck a paper towel against the grille if switched on with motor not running. Used and lightly abused, or aftermarket, or the motor swap. Be sure polarity is right so air blows toward engine block.
X2 on radiator, a clogged radiator may cool enough today at highway speed, but slow down and that 50% radiator can't keep up. With truck warmed up, engine off, touch the fins ant bottom and top. 10F cooler on bottom means you need to shop for an indy rad shop to rod it out. The fins won't be the 190F coolant temp, it has already dropped quite a bit by the air flow.
X2 on radiator, a clogged radiator may cool enough today at highway speed, but slow down and that 50% radiator can't keep up. With truck warmed up, engine off, touch the fins ant bottom and top. 10F cooler on bottom means you need to shop for an indy rad shop to rod it out. The fins won't be the 190F coolant temp, it has already dropped quite a bit by the air flow.
#17
07-12-2013, 04:53 PM
Join Date: Nov 2011
Location: Westerly, RI
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Clutch is frozen. Needs to be replaced. Will increase load on engine (poor mpg) and wear on water pump. If this has been going on for sometime, consider replacing water pump at same time. That said, it would not be source of overheat, as it increases airflow thru the radiator.
180F stat is an improvement of the situation. My D1 with 180K was running up to 221-227 in spikes, even with rad cleaned out by a shop. Put in a 180, it runs 178-183 on back roads and maybe 187 on expressway. In hot, humid, flat land with AC on.
When you slowed down to pull in driveway you have reduced air flow on the radiator.
The $10 thermostat is the cheapest part to throw at it. Also be sure your coolant cap is holding pressure and you are not having coolant loss while driving. If you have gurgle sounds under dash, then bubbles could be keeping thermostat and heat gauge sender from actually touching the hot water. Coolant needs to be full.
If you don't have an OBDII scanner, stop at a parts store for a free code read with one of their's, and while connected let them demo the live data capability. Look for coolant temp.
180F stat is an improvement of the situation. My D1 with 180K was running up to 221-227 in spikes, even with rad cleaned out by a shop. Put in a 180, it runs 178-183 on back roads and maybe 187 on expressway. In hot, humid, flat land with AC on.
When you slowed down to pull in driveway you have reduced air flow on the radiator.
The $10 thermostat is the cheapest part to throw at it. Also be sure your coolant cap is holding pressure and you are not having coolant loss while driving. If you have gurgle sounds under dash, then bubbles could be keeping thermostat and heat gauge sender from actually touching the hot water. Coolant needs to be full.
If you don't have an OBDII scanner, stop at a parts store for a free code read with one of their's, and while connected let them demo the live data capability. Look for coolant temp.
Also, the car still overheats after being driven for awhile with the heat off... if i put the heat on, the temp returns to normal.
#19
07-12-2013, 10:45 PM
Super Moderator
Radiator and heater core have crud in them. With truck warm, engine off, feel radiator fins top to bottom or use IR thermometer. More than 10F cooler on bottom indicates clogged rad, reduced flow (same air flow across surface, less hot water inside the rows of tubes at that point). You can reverse flush the heater core, they are not easy to change. Radiator can be rodded out, they unsolder a tank, runs about $75 near me. Once rad is crudded up, home brew and commercial flush products usually can't do much. They are preventative practices.
Don't drive with gauge above 9:00, and get a scanner to tell you real temps.
Don't drive with gauge above 9:00, and get a scanner to tell you real temps.
Last edited by Savannah Buzz; 07-12-2013 at 10:47 PM.
#20
07-13-2013, 08:35 PM
I had pretty much identical problems with my '98. Changed clutch, fan, thermostat, cap, flushed several times, tried some voodoo, waved a dead chicken over it, etc.
What finally worked was a replacement radiator. I got lucky and found a good one at the boneyard for something like $65. Looked for visible leaks (none) did a high-pressure flush (at the car wash) and let muriatic acid soak in it for a while (longer than recommended, for various reasons.)
If you don't trust your local pull-a-part pickins', just take it to get rodded & pressure tested before you install it.
What finally worked was a replacement radiator. I got lucky and found a good one at the boneyard for something like $65. Looked for visible leaks (none) did a high-pressure flush (at the car wash) and let muriatic acid soak in it for a while (longer than recommended, for various reasons.)
If you don't trust your local pull-a-part pickins', just take it to get rodded & pressure tested before you install it.