Community Forums

Fostfreez · 10-27-2011, 02:17 PM

I was taking my '04 34' with cummins isl motor to a shop to have the tv worked on when after driving 4 miles down the road I looked at the temp gauge and saw it was at 240 and rising. It was only 55 degrees out and I was on level road so I immediately pulled over and waited a couple of minutes to see if she would cool down any. After I shut the engine off I opened the engine compartment and looked for coolant leaks. There were none and the coolant level showed full. Any thoughts as to the most likely cause? Thermostat or radiator fan or ??

Thanks,

John Foster

gaugeguy · 10-27-2011, 05:07 PM

It appears the ISL has a range of coolant temperature issues throughout the years. When I used to work on them I never had one actually experience overheating. The problems I have seen include defective temperature sending unit (the one that sends the signal to the gauge/light) or wiring, stuck thermostat or an erratic ECM.
I found a website that stated Cummins engines run effectively with coolant temperatures between -40 to +140 centigrade (that's up to about 260 deg F).
You did not state what your normal engine coolant temperature was prior to the incident or if the engine actually smelled overheated when you checked it (a tell-tale sign for sure). My experience has been that if an engine goes from cold to extremely hot withing a few minutes ......... the thermostat should be checked out.
On the other hand, your local diesel shop can run some quick engine diagnostics to determine if the thing really did overheat and maybe the probable cause.
It's not something to mess with; overheating is never a good thing. Get it checked out.
Now, I've confused even myself. Good luck

EngineerMike · 10-27-2011, 07:40 PM

John- I doubt you could get to 240 after driving only 4 miles on flat ground. Probably a bad sending unit. IIRC there are two, one for the gauge and one for the engine's computer input. I believe 240 on the engine's input would be telling you to pull over & stop (I think the alarm comes on at 235).

Fostfreez · 10-27-2011, 10:05 PM

Thanks guys for the responses. Since I'm a new be DP owner and not much of a mechanic I will be the first admit that I'm slow to figure out what is actually going on. Mike I think you're probably on the right track. My engine usually runs at about 198 to 200. When I shut it down and opened the engine compartment it did not smell or feel hot to my face as I stuck my head in trying to look for a coolant leak. Is wise to replace the thermostat just in case them look into the sending unit at the engine? Is the sending unit a costly or difficult thing to replace? Thanks for all of the advice I know I'll be asking for a lot more.

John Foster

takepride · 10-27-2011, 11:31 PM

John:

Though with only going 4 miles, making eMike's response the most likely, I and several others have been tricked into thinking the coolant is full by looking at the sightglass when cool. It ought to be halfway up the glass, but residue often sticks in there, making it look full. However, when the engine is warm (or hot) it ought to look completely full (in the sightglass).

Jim A · 10-28-2011, 11:19 AM

In the past I have had the same thing happen two or three times on my coach. After only a couple of miles the temp reading would go way up and turn on the alarm. Pulling over and stopping, and restarting the engine fixed it, with the temperature reading back to normal (actually a little low) and everything fine. It hasn't done this in a few years.

It seemed to happen when I didn't have the temperature fully up to normal temp and put a load on it. I now try to avoid that condition more than I used to, so maybe that is why it hasn't happened in years.

Mule Skinner · 10-30-2011, 06:15 PM

My 04 came with a 8lb pressure cap (?) why, I don't know. I would see coolant on the ground once in a while. The site glass looked like there was plenty of coolant. After having the high temp alarm go off one day I started looking into this.
I found I was low on coolant. The site glass seemed to hold fluid even when the tank was low. The cap was 8lb. so, I drained the remaining coolant, refilled and replaced the cap with a 16lb.
That was two years ago and have not had a problem since.
Why I had a 8lb cap ??? Must have run out of 16lb or it was in the wrong box?

Renipladlo · 10-30-2011, 07:39 PM

FWIW - I have checked around and cannot find any place where there are cooling issues with the ISL. Not to say there are not, my guess is the reason is the way the coach manufacturers implement the cooling requirements versus Cummins specifications. I know Alpine went over the specification if I remember at least they said they did.

FWIW#2 - Today I climbed the hill out of the Bakersfield, CA valley into the LA area. I never got warmer than 202, because I shift down to 4th and keep the RPM’s at 1900-2100 going up those hills which keeps the cooling fans on High speed, since the Hydraulic pump is turning at max. I learned this from reading this here, so that is how to keep it cooler.

FWIW #3 – I weighted the coach prior to leaving Oregon, and front is 12790 rear is 19400, so I am near gross weight. My water tank was full and my diesel tank was half. So with full fuel I’m thinking I am close to gross weight.

So pulling that hill today and not hitting over 202 was good. It seems to be running cooler since I had the coolant changed last month. It also seems to be getting better fuel mileage but that is because I’m holding the line at 60mph, instead of my normal 63-65. Don’t need to be in a hurry.

Check the cap on the overflow/coolant tank, get a new one to be safe, the engine manual should have a specification on it, I think it’s supposed to be a 17lb pressure cap. Others can verify this. The temp sensor, should not be a big deal to change, depending on where you live any Cummins certified shop can do it for you. Since they are doing that, it might be time to change the coolant as well, as it’s supposed to be every three years or 150K miles, age gets us long before mileage, so I figure if you check the DCA level every year, you can go 4-5 years on the coolant. I know I will do mine myself the next time, since the labor was 102.00 and I could spend that money on fuel.

rmmpe · 10-30-2011, 07:45 PM

By Silverleaf or OEM gage?

Renipladlo · 10-30-2011, 11:17 PM

By the silverleaf guage, but I trust it more than the analog one, as it was just replaced friday with new programing and new tank sensors.

When driving the analog guages is too hard to read, the SL is nice and bright and has big numbers to view.

Bob I like you signature. How is the new rig working for you?

Fostfreez · 10-31-2011, 08:30 AM

Once again thanks for all of the input. It is a great stress reliever for a rookie like me. I'm really glad I found the IRV2 forum and especially the Alpine Owners group. We know that Alpine and this 34' were the perfect choice for us!
Anyway back to the problem. Since the coach was in the shop for the tv I had them replace the thermostat. We took her out for 300 mile weekend camping trip up to Lone Pine. I'm happy to report that she ran at about 195, maybe nudging 200 once or twice on a hill. I still think that what I saw was temp gauge/sensor malfunction like some of you guys. I am going to go get a new radiator cap. I'll let you all know if the problem stays solved. Thanks for the support.

John & Lorraine Foster
'04, 34' FDDS, ISL 400

rmmpe · 10-31-2011, 08:53 AM

Hi Monty,
Actually, I asked that question of the OP. Like you, I trusted the SL far more than the OEM gages. I wish they had a VMSPC for our new unit.

This is the 3rd Phoenix we've owned in the 14 months since trading the Alpine. The 1st, although a very nice unit, was too small after making an 11,561-mile trip. We then bought a 2010 2551 with twin beds but no place for a lounge chair or table. On the way back from a trip we stopped at the factory to buy a Cherry tabletop I was going to make a Hi-Lo table from. When walking back through the shop with a tabletop under my arm I passed a new 2552 and heard "Honey, could you come in here for a minute?" Boy, that's the most expensive piece of wood I ever bought.

But, in truth, as good as the Phoenix is and as happy as we are with it, I still miss our Alpine. It was pretty good when we bought it and better when we sold it. However, Peg was never really comfortable in it and is very much at ease now.

The new owner of the Alpine and I have been conversing back and forth quite a lot and I believe it's found a good home. He lives in the same town as our in-laws and we'll probably get there in the next few years. Maybe we can meet then.

Keep safe and happy trails.

Bob

EngineerMike · 10-31-2011, 10:15 AM

FYI- the gauges in the OP's 04, and everybody else's since (and I think all Alpines since new but I haven't done a review on the full lineage of gauge sets), are not analog gauges, they are servo-motor-driven-analog faces on digital gauges. I believe the only thing analog in the stream is the original analog sensor (temp sensors, vehicle speed sensor, etc) whose signal is converted by some device to digital information. In the case of earlier year rigs, the VDC, a box containing electronics and located behind the battery box in some rigs, translated signals of various inputs to digital; in the case of 05+ rigs the ECU and/or Vansco translates the signals to digital. So the signals reported by the various versions of Silverleaf (which reads/reports ECU info where available UIMMG) differ from gauge info only where the gauge has a secondary sender, in which case you could get different readings between gauge & Silverleaf.

Mule Skinner · 10-31-2011, 10:28 AM

Just to be clear, I changed the cap on the recovery/fill tank, (same type of cap).
But, you might also check the radiator cap as well.

Good Luck

Quote:

Originally Posted by Fostfreez

Once again thanks for all of the input. It is a great stress reliever for a rookie like me. I'm really glad I found the IRV2 forum and especially the Alpine Owners group. We know that Alpine and this 34' were the perfect choice for us!
Anyway back to the problem. Since the coach was in the shop for the tv I had them replace the thermostat. We took her out for 300 mile weekend camping trip up to Lone Pine. I'm happy to report that she ran at about 195, maybe nudging 200 once or twice on a hill. I still think that what I saw was temp gauge/sensor malfunction like some of you guys. I am going to go get a new radiator cap. I'll let you all know if the problem stays solved. Thanks for the support.

John & Lorraine Foster
'04, 34' FDDS, ISL 400