1998 Ram 1500 Overheating/Gremlins

[CocaineCowboy]

I have a 1998 Dodge Ram 1500 Laramie 4x4. It is my first 4x4 and I love it. Recently, I've been running into small gremlins with it. For example, I started the truck one afternoon and the transmission wouldn't fully go into gear. It's an automatic, and it's like it was stuck in between gears. The truck stalled, I restarted it, and it ran fine. It does weird stuff like that all the time. Within the last 2 weeks, I've had multiple occasions where the temp gage says the truck is running below 210, but instead its running at around 240 (at least that what the thermal shows on the engine block). The coolant is new in the truck, and my mechanic checked the radiator and the water pump, both showed to be in good shape. I have not found a single leak in the system anywhere. Could there be an internal blockage somewhere from years of wear and abuse? This truck was owned by several teenagers over the years and I am one myself. I'm not a mechanic but have been taught a few things and am currently a mechanic's assistant at a shop in town. Any assistance on figuring this out would be heavily appreciated.
Thanks, Max.

 

[dudeman2009]

I have a 1998 Dodge Ram 1500 Laramie 4x4. It is my first 4x4 and I love it. Recently, I've been running into small gremlins with it. For example, I started the truck one afternoon and the transmission wouldn't fully go into gear. It's an automatic, and it's like it was stuck in between gears. The truck stalled, I restarted it, and it ran fine. It does weird stuff like that all the time. Within the last 2 weeks, I've had multiple occasions where the temp gage says the truck is running below 210, but instead its running at around 240 (at least that what the thermal shows on the engine block). The coolant is new in the truck, and my mechanic checked the radiator and the water pump, both showed to be in good shape. I have not found a single leak in the system anywhere. Could there be an internal blockage somewhere from years of wear and abuse? This truck was owned by several teenagers over the years and I am one myself. I'm not a mechanic but have been taught a few things and am currently a mechanic's assistant at a shop in town. Any assistance on figuring this out would be heavily appreciated.
Thanks, Max.

For temps, you need to read on the coolant hose coming from the block to the radiator. The block will be hotter than the coolant, especially near the exhaust manifold. Take a thermocouple or non contact thermometer (non contact will be off a bit) and measure there. Dont try to stop the fan, but instead put cardboard over the AC condensor to reduce airflow. Wait until it gets to about 220 then remove the cardboard and note how fast the temp drops. It should go back to about 210 within a minute or two.
Check the temp with a scantool not the gauge, for some reason the temp gauge is not linear. Mine has never gotten to 210, except once in the winter when the thermostat froze shut. So I don't know if 210 on the gauge is really 210 or not. I know where 180 lies xD

As for the transmission, check the fluid color, stalling may be indicative of a few things, but check the color first. It shouldn't be any more brown than a wendys or tacobell napkin. If its good, or bad, fluid and filter change. Can never go wrong with a fluid and filter change. It will also give you a chance to do a band adjustment. That could be part of the problem. Usually though, stalling is a torque converter issue, at least in the semis I used to work on. Auto, im not as sure.

 

[CocaineCowboy]

For temps, you need to read on the coolant hose coming from the block to the radiator. The block will be hotter than the coolant, especially near the exhaust manifold. Take a thermocouple or non contact thermometer (non contact will be off a bit) and measure there. Dont try to stop the fan, but instead put cardboard over the AC condensor to reduce airflow. Wait until it gets to about 220 then remove the cardboard and note how fast the temp drops. It should go back to about 210 within a minute or two.
Check the temp with a scantool not the gauge, for some reason the temp gauge is not linear. Mine has never gotten to 210, except once in the winter when the thermostat froze shut. So I don't know if 210 on the gauge is really 210 or not. I know where 180 lies xD

As for the transmission, check the fluid color, stalling may be indicative of a few things, but check the color first. It shouldn't be any more brown than a wendys or tacobell napkin. If its good, or bad, fluid and filter change. Can never go wrong with a fluid and filter change. It will also give you a chance to do a band adjustment. That could be part of the problem. Usually though, stalling is a torque converter issue, at least in the semis I used to work on. Auto, im not as sure.

Thanks for the reply. The transmission fluid and filter were replaced before I got the truck. The bands were not adjusted in any way, so I may have to look into that more. It's the only time that it has happened, so it'll be on the back-burner for now.
As far as the overheating goes, I put a non-contact on the radiator hose flowing from the engine to the radiator and it still showed almost 230 degrees. When the truck gets hot, it will lose almost all power, and can only crawl along. On the highway, it can only manage about 50 mph when the temperature climbs. When it's cooler outside, (less than the 95 -100 degrees we've been seeing all year) it runs fine, and has good power throughout the rev-range. Until it cools down for the season, should I try a coolant flush or check the thermostat? The thermostat is located on the top of the block near the intake, and would probably require the alternator and the A/C compressor to be taken off at least. It's never been done from what I understand, and the truck is just crossing 200,000 miles. Let me know if I'm missing anything on this, because I'd like to keep the truck around as long as possible. I've been plotting in my mind and on paper about a 24v cummins swap from a roll-over truck on my friends property. Thanks, Max (aka, dumbest Mopar guy ever)

 

[dudeman2009]

Thanks for the reply. The transmission fluid and filter were replaced before I got the truck. The bands were not adjusted in any way, so I may have to look into that more. It's the only time that it has happened, so it'll be on the back-burner for now.
As far as the overheating goes, I put a non-contact on the radiator hose flowing from the engine to the radiator and it still showed almost 230 degrees. When the truck gets hot, it will lose almost all power, and can only crawl along. On the highway, it can only manage about 50 mph when the temperature climbs. When it's cooler outside, (less than the 95 -100 degrees we've been seeing all year) it runs fine, and has good power throughout the rev-range. Until it cools down for the season, should I try a coolant flush or check the thermostat? The thermostat is located on the top of the block near the intake, and would probably require the alternator and the A/C compressor to be taken off at least. It's never been done from what I understand, and the truck is just crossing 200,000 miles. Let me know if I'm missing anything on this, because I'd like to keep the truck around as long as possible. I've been plotting in my mind and on paper about a 24v cummins swap from a roll-over truck on my friends property. Thanks, Max (aka, dumbest Mopar guy ever)

I happen to love the 24v, but that would be a lot of work. If it was a roll over, i'd rebuilt it first.

As for overheating, You will want to run 10w-40 or maybe even 15w-40 if temps don't get below 0F, that will reduce some engine resistance and by extension heat in those high temps. I would change the thermostat and coolant. Overtime coolant loses its ability to properly cool, and thermostats can lose their ability to completely open.

You can get the thermostat out without removing anything, but its much easier to remove the alternator bracket, you dont need to mess with the compressor.

For coolant, you should work to achieve a 50/5- mix. I use the Prestone (Ithink its the name) green fluid. Works great, color is irrelevant at that point.

For the thermostat, I put a thin film of rtv on the gasket before application.

A proper flush and reverse flush is a good idea.

 

[dapepper9]

^^dudeman has ya covered pretty well but i would add that anti-seize on the thermostat housing bolts is a good idea. You don't really want to break them the next time and they've been known to

 

[CocaineCowboy]

I happen to love the 24v, but that would be a lot of work. If it was a roll over, i'd rebuilt it first.

As for overheating, You will want to run 10w-40 or maybe even 15w-40 if temps don't get below 0F, that will reduce some engine resistance and by extension heat in those high temps. I would change the thermostat and coolant. Overtime coolant loses its ability to properly cool, and thermostats can lose their ability to completely open.

You can get the thermostat out without removing anything, but its much easier to remove the alternator bracket, you dont need to mess with the compressor.

For coolant, you should work to achieve a 50/5- mix. I use the Prestone (Ithink its the name) green fluid. Works great, color is irrelevant at that point.

For the thermostat, I put a thin film of rtv on the gasket before application.

A proper flush and reverse flush is a good idea.

^^dudeman has ya covered pretty well but i would add that anti-seize on the thermostat housing bolts is a good idea. You don't really want to break them the next time and they've been known to

Thanks for the help. I'll be putting in the thermostat when I get the money. Hopefully the truck will be running somewhere between 190 and 210 by the time this is done. Next step, tube bumpers and rock sliders!

 

[CocaineCowboy]

Got the new thermostat and new coolant in today, truck is running great. Truck is running like new. Thank you dapepper9 and dudeman2009. My next dumb decision (jump, drift, or smashed fence) will be carried out in your honor.