Hello everyone, I'm new to the site and this is my first diesel. I just picked up a 99 2500 long bed 4x4 5 speed manual. Truck has 310k on it and according to the service records the truck has been maintained well. My question is what temp should the thermostat open up at? When driving from cold the thermostat goes past 190 to probably 215 or 220 then opens up and drops back down to 180-190. It never over heats, but it is the initial opening that makes me wonder if the thermostat is sticking. When it goes over 190 the cab has a little bit of a sweet antifreeze smell but I have checked under the hood and there are no leaks. It just smells hot when it first opens up. I can drive the rest of the day and not have that issue at all. Is this normal for this truck? Truck has the idiot fuel pressure light and a 4" exhaust from the cab back. 

Those temps sound about right.  If you don't know the last time the coolant was serviced you ought to consider doing a flush.  If your crank case vent is stock you would need to pull the radiator and clean that as well.  It is simple insurance.

 

Welcome to the site. 

welcome.  the smell isn't normal, however it is normal for the temp to overshoot and then settle down.  the trucks have an oversized cooling system, and work well.  you should consider pulling the radiator and cleaning it along with changing your coolant.  coolant turns acidic over time and the factory oil breather likely covered the fan and radiator with oil and dirt.  

 

i dont like idiot lights.  gauges will give you a much better eye on stuff.

Thanks, I will do a flush on the cooling system and check or replace the crank case vent. The idiot light came with the truck and I don't really care for it. I would like to put gauges in and get some kind of chip for the truck.  A buddy of mine worked for Edge Products and is telling me to not buy gauges but look for the Edge Juice + Attitude. It looks like the attitude will monitor boost, egt, and fuel pressure. Would you do mechanical gauges and the edge piece or is it safe to rely on just the edge gauges?

The edge is a pretty reliable unit. I think you would be safe either way, it's just a matter of preference.

First of all, I just want to point out that the antifreeze smell in the cab could be your heater core leaking. You can check the passenger side floor and firewall to see if you can find anything wet with antifreeze. 

 

As as far as gauges go, there is nothing wrong with an edge monitor or something like the quad that have gauges and all kinds of bells and whistles, if you like that kind of thing. Keep in mind though, you still have to drill and tap the exhaust manifold for your pyro probe, and you have to tap into the fuel system and install a pressure sender for fuel pressure, and install a boost pressure sender as well. I believe the juice w/attitude does give you other features like a turbo timer and the ability to read an clear codes though and I think, so does the quad. You can confirm all the specs on their websites though or you can call. Most of these companies are pretty helpful. The downside to a monitor with gauges is, if it stops working for whatever reason, or if you want to try a different tuner like a smarty or edge comp that doesn't have gauges, you have no idea where your at and if your parameters are safe or not. In my opinion, it's good to have the three big ones(fuel pressure, pyro, and boost) as dedicated gauges on the a pillar or in the dash or wherever you like. Fuel pressure is a must at very minimum with pyro as a close second especially if you have any power mods like injectors or tuner. Boost is more just handy for diagnostic purposes. Whatever you do, don't get glowshift! Get something from a reputable company like Autometer or Isspro. Both have very good customer service. Also, if you are looking for a pillar pod, you can pick up a cheap one of those on eBay than add gauges of your choice  and of course it never hurts to have gauges and a monitor Also, just a though, the juice with attitude is a powerful box. If you don't need all that, you can do an edge ez and gauges, or if you want the power but not the monitor, you can do an edge comp and gauges. Of course just because you have the power doesn't mean you have to use it. So far I've had a Smarty and Edge Comp. I like the look of the triple gauges on the pilar.

1 hour ago, xmtysonxm said:

My question is what temp should the thermostat open up at? When driving from cold the thermostat goes past 190 to probably 215 or 220 then opens up and drops back down to 180-190.

 

Take notice to my coolant gauge here I've marked the green area as normal. You can see the open temperature of my thermostat. So I would have to say your thermostat is sticking.

 

1 hour ago, xmtysonxm said:

When it goes over 190 the cab has a little bit of a sweet antifreeze smell but I have checked under the hood and there are no leaks.

 

Heater core is going south if your smelling anti-freeze in the cab. Most likely got a small crack and the expanding coolant with pressure is force out a small crack or pin hole.

 

1 hour ago, xmtysonxm said:

Truck has the idiot fuel pressure light

 

Highly suggest a fuel pressure gauge. Most idiot light come on way too low. Like my old Cummins low fuel pressure would trip at 3.5 PSI. You need to be able to keep 14-20 PSI optimally. 10 PSI is stock low fuel pressure limit.

Thank you everyone for your input. This site has a wealth of information! I will get some ISSPRO gauges coming and check for a heater core leak, replace the thermostat and flush the cooling system.

ISSPro EV are mechanical...

 

ISSPro EV2 are electronic programmable.

 

 

16 minutes ago, xmtysonxm said:

Thank you everyone for your input. This site has a wealth of information! I will get some ISSPRO gauges coming and check for a heater core leak, replace the thermostat and flush the cooling system.

If you are going to flush the coolant don't forget to pull the radiator and clean that well.  It is simple to remove and it will save you a headache in the future.  The way the crankcase vents it leave oil residue on the radiator which in turn traps grit and grime that blocks air flow and prevents cooling.  I did mine last year and I was surprised at how bad it actually was. 

Yes it's normal to overshoot a little on the initial opening; however, that overshoot shouldn't regularly go more than 195-198° and if it does it's time for a thermostat replacement. 

 

With the LARGE cooling system on these trucks and the 17° range from cracking to full open (190° crack, 207° full open) it's not abnormal to develop a wear spot on the thermostat if they don't often see loads sufficient to get the thermostat to fully open. It takes a decent load for that to happen, more than just a small trailer. Yesterday I pulled a 7 mile grade with 7-10% sections at 70 mph in 110° heat and only got to 204°. No trailer and no load, about 8600 lbs GVW. The cooling systems are efficient!

It's also hard to trust the dash gauge for %100 accuracy. On my 02 I've found that the gauge is roughly 2-3* off. So if my gauge reads 189-190* it's really in the 193-195* range and then my thermostat will open shortly after. This is all just empty cruising around town but just food for thought.

46 minutes ago, notlimah said:

It's also hard to trust the dash gauge for %100 accuracy. On my 02 I've found that the gauge is roughly 2-3* off. So if my gauge reads 189-190* it's really in the 193-195* range and then my thermostat will open shortly after. This is all just empty cruising around town but just food for thought.

I see the same thing. It takes over 195 for my gauge to read over 195. Also, 188 shows like 183ish on the dash.

Edited June 20, 20168 yr by TFaoro

As long as it stays stable when its warmed up and running at a steady speed, I don't care.  When its summer and I am pulling heavy with AC on, I just want to see any swings stay within the normal range.  

How are you guys getting that accurate a number off the dash gauge? I see under 190* or over 190*

I can't speak for the other guys but what I'd assume they're talking about, as am I, is using something like a scangauge, OBDIImx or any other tool that reads real time coolant temps and then comparing the two temps at a like point. I just waited until my dash gauge read 190* and then checked my OBDII and it said 194-195* so I knew my gauge was a little off and on the low side.

I've got a scangauge, and a quadzilla monitor. I'm guessing what the gauge in the dash is reading.

Dash gauge for the most part is correct and accurate. It's just digital displays give a absolute number where the needle on the dash might barely move hard to see a 5* change on the dash where like ScanGauge II or OBDLink will show an absolute number. As long as the needle stays in the normal bracket of the gauge you should be fine.

 

 

What is the high side of the normal bracket?  I have never compared temp vs the upper end

If I remember right its 225*F.

 

On June 20, 2016 at 0:04 PM, Mopar1973Man said:

 

Take notice to my coolant gauge here I've marked the green area as normal. You can see the open temperature of my thermostat. So I would have to say your thermostat is sticking.

 

 

Heater core is going south if your smelling anti-freeze in the cab. Most likely got a small crack and the expanding coolant with pressure is force out a small crack or pin hole.

 

 

Highly suggest a fuel pressure gauge. Most idiot light come on way too low. Like my old Cummins low fuel pressure would trip at 3.5 PSI. You need to be able to keep 14-20 PSI optimally. 10 PSI is stock low fuel pressure limit.

What monitor or programmer are you running?