Hello,

94 disco I, 97K.
So about a 3 weeks ago I had to fill up after only going 160miles on a full tank (about 6mpg). I used to get 12-13mpg after I put in plat +4 plugs, magnacore, synthetic fluids etc. Then this happens. I figured maybe because of the cold I was letting it idle too long (about two min) because of the cold (single digits to below zero, I live in Northern IL). After a fill up, I stopped letting it idle so long (maybe 30sec) but the MPG still sucked. Now I've gone through my third full tank at 6mpg. The 2 digit code reader built in isn't giving anything and the exhaust smells gasier than usual (maybe I'm just thinking it does?). I've been using the same 91oct gas I always use. Only difference is that the radiator started making a "gurgling" noise at the same time I noticed the gas problem. The coolant tank was about 1/4 full (halfway to the fill mark). The car does consume a little bit of coolant, about 1/2 the tank's amount every 6months or so. Finally the fan pulley is bouncing around at idle about a 1/4-1/2inch in and out.

Are these problems related? I'd like to take care of the MPG issue first since that seems more difficult and serious.

Thanks,
RM

 

ok, first of all, although sniffing your tailpipe is cheaper than buying drugs, the effects are far more harmful, so stop doing that!!
secondly, losing that much coolant over that period of time would indicate to me that you have a leak somewhere, so get to looking. the coolant problem is far more important right now than the MPG being lower right now. there are any number of reasons why that could have dropped....driving habits, cold weather, etc, etc, etc.....but 6 MPG is really low...even for these trucks.
and lastly, the fan pully....how are you determining thats is "bouncing" around?? while it is spinning, it will look like it might be doing that?? have you used a timing light to observe the "bouncing"? that might give you a truer sense of what its doing.

 

It sounds like your water pump has failed causing the movement in the water pump pulley. Do not drive it in this condition, or open the hood and look at it or stand in line with the fan while the engine is running, it may break any minute causing the fan to come loose and injure some one. Fix this one first before you do anything else.

You mention hearing a gurgling noise in the radiator, that is a sign of overheating, are your head gaskets OK?. Head gasket failure causes misfire, this causes a drop in gas mileage.

 

not standing inline with the fan on a running engine is a good safety tip for ANY vehicle. If I were you I would go to a local parts store that loans tools and get a coolant pressure tester.

 

Hey Disco mike,

The pulley seems loose just by looking at it spin because its bouncing in and out about 1/4-1/2inch while other pulleys just spin on axis without play. When the engine is cold and off the pulley is moveable by hand while others aren't. About the coolant loss: the loss is from coolant tank fill mark to about 3/4inch left in tank, then it stops losing coolant altogther.

Unigomed: I don't think its overheating becauase the sound is there on a cold start in the morning with outside temps in single digits or below zero. The sound goes away with higher rpms though.

One more thing: I check coolant's specific gravity and its really high. When I drained an filled 4-5months ago, I put in 50/50 so I think its losing water and leaving coolant behind.

Any thoughts on MPG? I can't afford to drive it at this rate.

Thanks,
RM

 

You can't afford to drive it until you fix the coolant problem. and it is sounding more and more like the water pump is about to go. GET IT FIXED!!! then worry about the MPG!

 

You need a new water pump. FIX IT OR YOU WONT BE DRIVING AT ALL!!
The gurgling sound you hear is a air bubble in your cooling system.
As for the MPG...when it is that cold out the truck needs to warm up longer.
15 mins when it is below zero, 10 when below 20 and 5 is good when below 40.
A cold engine is a ineffecient engine, you will use more gas in the winter, period. Different blend of gas (winter gas).
I have been experimenting with my truck this winter.
If I let it warm up for 10-15 minutes in the morning before work and again when leaving work I can drive back and forth to work for two weeks on half a tank of gas.
If I give it 5 mins or less to warm up then I can only drive one week on just under half a tank of gas.
So less idle time but I use more gas.
So let it warm up when it is so cold, the temp gauge should be past the lowest hash mark on the temp gauge before you start driving. Then drive slow until the temp gauge reads normal, middle of the gauge is normal.

 

When it comes to water pumps: is after market ok? Also I read that I have to take off the fan and viscous clutch too which require special tools. Any way to avoid the special tools? Should I replace the viscous clutch? I bought the car used at 90K miles without repair history.

 

Yes aftermarket pumps are fine, yes replace the viscous clutch, buy a used one.
All you need is the correct size wrench, I bought a 38mm cresent wrench, you can also rent the tools from NAPA.

 

which tools would I rent for the water pump job? (I'm bad with tool names) Also, by used viscous clutch do you mean rebuilt or straight used? Do you think mine got messed up from the bad water pump?