Dakota Forumz banner
1 - 4 of 4 Posts

·
Registered
Joined
·
13 Posts
Discussion Starter · #1 ·
Good morning class. My 98 3.9 dakota sport 2wd has a few issues to get sorted out. Starting with the engine temperature. The gauge never goes but a hair over 130 degrees. When I have hooked up scan tool, the real time events shows about 144 degrees running. After 30 minutes of driving I can stick a finger in the radiator and its just warm....I would imagine that should be scolding hot?
I tried flushing and back flushing the heater core, and that made no difference. I believe because the coolant just doesn't get hot.

I have no engine codes.

My other problem is a slight engine idling surge and I think it is idling high too;(1200rpm) I replaced the iac valve and throttle position sensor. When I removed the iac it was covered in so much gunk, I decided to take the throttle body off and clean it also. After all that it idles at 1000rpm now and still surges a little.
Also gets terrible fuel economy 12.5mpg.

I'm getting ready to replace the thermostat with a 195 I picked up from the dealer. The Haynes manual seems to think its something else because I have no check engine light codes. It has a new fan clutch, most likely a different junkyard radiator, different engine, possibly transmission too.

The truck has been nothing but a can of worms after another. Ive read all over the Internet about no heat problems with possible solutions, but I haven't found one that quite fits the bill.

I'm thinking the bad fuel economy may be because the engine never really warms up right. Maybe that could also be my no heat problem? I've seen several places that a new thermostat has been tried and still did not fix anything. Well, I have one so ill give it a try. Far as the engine surging, I think the only things left are the map sensor and air temperature sensor.
 

·
Registered
Joined
·
13 Posts
Discussion Starter · #2 ·
Well, figured I'd give an update that might help if anyone is having these same problems down the road. I installed a new 195 degree thermostat and now I have heat! I tried to do it the "right way" at first with just a gasket....well that diddnt go so well. I ended up RTV blue goo the heck out of that thing. Let it cure overnight and not a single drop.

To clarify, my temperature gauge is going up quite a bit further than it used to, but still not straight up and down at the 210 mark. About 1/4 way up. My heat works pretty good now....I also put in a new ambient air temperature sensor. Because my truck diddnt have one..it was wrecked and has a few loose wires hanging around the front. I thought it was for the airbags, or fog lights? Maybe that's what my other 2 connections are for?
 

·
Registered
Joined
·
13 Posts
Discussion Starter · #3 ·
So, I just filled up and my fuel economy seemed to improve to around 14.5 MPG. Still idles a little high at 1000rpm and the engine still surges 50 rpm+-.
From what I have been reading that seems pretty average economy for this truck.
 
1 - 4 of 4 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top