Check Engine Light Intermittent

[Carl Boger]

I tried a online search but there are to many results for me to get through them all.  This will also be a little long winded to provide the needed background.

We just returned from our first real trip in over a year and our first extended tow of a CRV.  We had towed it in April, but it was only a little over 100 miles each way.  This time we went to Charleston SC, probably just over 300 miles away from my home. The trip down was normal, Cat 3126 ran great, tow of the CRV was fine and temps were only in the high 70's or low 80's.  We set up had a great weekend and left this morning around 930 or 10.

Just after we passed through Columbia and got on I 77 heading north the Check engine light started to come on and then would go off.  The outside temperature was around 90 degrees and I was down near 1/2 tank of Diesel so I pulled off and put topped off with Diesel. I also checked the oil level which was within the  normal range, but I have never actually marked the engine oil level when it was newly filled with fresh oil.  Seeing that it was slightly below the top line I decided to add 2 quarts of oil.  I also used the cruise control to look for any codes.  I got a code 55 which my manual stated was no codes stored.  Took off down the road and no check engine light for about the first 10 miles, then it started it again.

I started to check my temperature information on my magnum intellidrive.  Intake manifold temp was from 151 to 156.  Transmission oil was 226 to 235. Coolant temp was from 208 to 221.   My oil pressure on the mechanical dash gauge stayed around 35 psi.  The coach also started to occasionally loose some power climbing the hills outside of Columbia.   At first I thought maybe the cat was de-rating the engine, but now I believe it may have been a fuel or filter issue. 

At this point I was maybe 70 miles from home so I stopped and disconnected the TOAD and transferred my wife and dogs to it to drive the rest of the way home thinking towing may be causing the issue at 90 degrees.  Well it ran slightly better without the TOAD but the check engine light still kept coming on and going off.  I also had the fuel issue where occasionally it would be down on power and then it would have decent power again. 

I drove probably 30 to 40 miles this way and the power/fuel issue seemed to go away, but the on and off check engine light was still there.  I was also driving about 59 to 62 mph the total time.

When I got off of the Interstates or local roads with interstate speeds.  The Check engine light went away.  Most of this was at 45 to 50 mph speeds.  The last 3 miles 35 to 40mph.  So about 12 miles where everything seemed to be normal. 

I am home now and have checked the coolant level it is normal.  Oil level is normal, and the Trans level is normal.  My fuel filter is a Parker S3230P, and currently  I have a Wix 33377 secondary filter.

I have less that 2000 miles since the oil was changed, but since I did not go anywhere last year with covid I was waiting until after this trip to change the oil.

Now I am thinking about changing the oil and filter.  Changing the Transmission fluid and changing out the fuel filters going back to a cat filter as the secondary.  I was planning to do all of this this year anyway.

I really don't think 90 degrees is hot enough to cause all of these problems.  I do think that getting down to 1/2 a tank of diesel may have helped clog up the fuel filters, and maybe the fresh fuel helped get some clean fuel to finally work its way through.

I am open to ideas of problems to look for. 

I also apologize if I can not get back to you in a timely manner for a little bit.  I have a family emergency that will keep me busy as away from my coach a computer for a while.

Thanks for any help.  I hope to go on another short trim in 2 weeks.

[Richard Davis]

Carl
Have you checked the tension on the water pump belt?  (It is a totally separate belt from the serpentine belt.)  I had the same issues on my 3126.  The small water pump belt had worn and was loose and was slipping.  It is difficult to adjust that little belt in such tight quarters, but with the correct angle 1/2 inch socket wrench, you can get to it.  Hope that is all your problem is.

Richard

[Steve Huber]

Carl,
208-221 is too hot for a 3126 in non-mountain driving. I suspect the intermittent check engine light was due to the temperature varying above and below the trigger point as you drove. As Richard  mentioned your engine has a direct drive water pump. It also has a direct drive fan. Lugging the engine, as will occur when climbing even slight inclines using cruise control, can cause engine temp to increase due to slower fan and water pump speeds as they are dependent on engine RPM. On a rear radiator, direct drive fan engine, RPM is key in keeping engine temps manageable. So, when driving, especially in hilly country, keep your eye on engine temp and if it starts to climb, downshift to get the RPM back up. Don't worry about speed.
Another cause of hot running engines is a dirty radiator. If you haven't cleaned it, do so. Also check to see that the crank case ventilation (slobber) tube isn't venting below the engine in line with the radiator. If it is, reroute it (I used a PVC tube) to the side or back against the mud flap. You want to ensure the gunk coming out of it isn't carried into the radiator. A good way to check the condition of the radiator is to set the idle at about 1000 and go to the back as see how much of the radiator is actually exhausting the fan output. You should feel air pretty much over the entire surface. There are a number of posts on cleaning the radiator. To summarize, get it warm. Wet it down. Spray a mixture of Dawn and water on the complete surface and let it set a few minutes. Then rinse the radiator completely from both front and back. Consider cleaning you radiator at least annually or have your service shop do it during you annual service.
Good Luck.
Steve

[Carl Boger]

Thanks Richard and Steve,

I had just recently cleaned the radiator, but I will have to check the tightness of the water pump belt.  The RPM's may be part of the issue as I did have the cruise on and with the traffic may not have been as aggressive about adding fuel at the bottom of the hills.  At one time before it was flashing the check engine light I had left it down in 5th for probably 20 miles.  Once it was heating up I suspect that it was just hard to get the temps down.

I would still like to get new fluids for a known good starting point.  Hopefully I will be able to check it out some today, but probably not.

Any idea why the trans oil temp was so high?  The mechanical  gauges did not move to much but they were both over 200.  Maybe I should have just left it down shifted to 5th gear.  It is hard to remember everything that happened now.  It did seem to run well after I got off the interstate so hopefully this is something simple.

[Steve Huber]

Carl,
Transmission temps normally run a bit higher than engine temps. Also, you will often get cooler engine temps by running in 5th due to the higher RPM needed to attain your desired speed. I once ran almost all the way across OK in 5th due to the high outside temps (110+) since it kept engine temp down.
Steve

[Carl Boger]

Thanks Steve, and good call on the belt Richard. I am making the call that if you can spin the idler pulley with your fingers it is to loose.
I can not really see in there, but by feel I am guessing that if you loosen that bolt you can then pry the bracket downward with a pry bar and add tension.  If it has to move out farther than I am probably at the end of my belt adjustment. 

Unfortunately I have not been able to get the bolt loose.  I have gotten a off set wrench on it a couple of times, but not at an angle that I could break it free.  It is also a oily mess under there.  I only wish my engine was as clean as some of the others I have seen. 

I may go wrench shopping tonight if possible.  Hopefully the belt is THE issue, but I am sure it is A issue.  I may have to try to find someone to do this for me which is usually harder than just doing it myself.

Also while driving I had noticed that the light would go out when I was applying fuel going up a hill, and then come back on when I let off to coast some. Make since that the belt was tighter under power and would then loosen up.

[Eric Maclean Co-Admin]

Carl
If that belt has been slipping it's likely glazed at best and cooked and hardened at worst and may be prone to failure at this point.
This might be a good time to replace the water pump belt .It's a 1/2x34.02 inches      CAT# 036-6775.   NAPA 25-08755
The serpentine accessory belt is a NAPA 25-080700.

Hope this helps
Eric

[Richard Davis]

Carl
When I had to adjust the water pump belt on mine, I was in a campground in Colorado.  None of the 1/2 inch 12 point box-end wrenches I had with me were the correct side angle to get on that idler adjustment bolt.  I went to 3 parts houses before I found one that would fit.  Then the issue was getting enough torque on the wrench to loosen that bolt.  I had to use a piece of pipe for an extension as well as holding my mouth right and saying the magic words (words that are not repeatable).  I finally got the job done.  No more overheating.  The bad part; I eventually determined that my overheating issues had coked up my Turbo.  I hope you do not have that issue, but after you get the water pump spinning correctly and solve your overheating, pay attention to Turbo spin-up.  A sluggish Turbo spin-up can be a real drag (literally).  Good luck.

Richard

[Carl Boger]

Thanks Richard,
Since this just started I am hoping that I get lucky about it not being to hot.  Since I  am so slammed this week I called a local Diesel shop and ask if they cold change the fluids, filters and belts.  He said that he was pretty busy but that he would try to work me in if I dropped it by next Tuesday, so I could go out of town next Thursday.  I may have to cancel my reservation, but I at least have a chance.

Eric,
Thanks yet again for the part numbers.  I may well go by NAPA and get both belts to have as spares.  I will let the shop use them if they want, but if they would like to provide their own parts I am fine with that also.
I like to use local shops as long as they provide good service.  I have only talked to this shop in the past, but he seems to know what he is doing.  When I told him it was a 1998 cat he knew it was a 3126 and that the belt and adjuster are hard to get to.  Still he was willing to try to work me in.

[Eric Maclean Co-Admin]

Carl
If I remember properly the easiest way to get to the water pump idler adjustment is to remove the serpentine belt tensioner first.
The biggest part of changing out the belts is removing the hydralic pump and sliding it back to get the belts on and off the end of the  crankshaft that's why I would suggest they replace both belts while they're in there. And also check the hydralic pump drive coupler at the same time.

The hydraulic drive coupler was built for Beaver by a company called Magnaloy the part numbers are as follows
Engine side coupler is Magnaloy # M500-301-20042
Pump side coupler is Magnaloy  # M500-B10008SRC
coupler drive insert is Magnaloy # M570H5

The drive coupler inserts do ware out and if left long enough the cast coupler parts will ware as well it's important that the coupler be aligned properly to avoid accelorated insert ware.

Hope this helps
Eric

[Carl Boger]

Ok to continue this saga,

I had both belts replaced and the engine oil and filter changed as well as the fuel filters.  I thought this would fix my issue.

Today I drove to Galax Va in the mountains of Va/NC pulling my CRV.  Now this is uphill, but not like real mountains.  On the way up I was running about 63 mph when I noticed that the check engine light flickered and the temps were rising,  I slowed down 55 and the temps dropped and the light stayed off.  I got stuck in construction traffic on I-77 for about 1 hour and 20 minutes and the Temps cooled way off.  I did 3 1/2 miles of this until I could get off and detour around the construction area. 

I got to the hwy I needed to and started up the grade.  This was about a 4 mile uphill stretch with no where for me to pull off for most of it.  Well the temps started rising, the check engine light came on, and the MH started going slower and slower, anyone who could pass me did.  I think I got down to about 15 mph before I finally found a pull out, which I gladly pulled into.    I stayed there with the engine running for probably 5 minutes and the light went out, the temps dropped, and the engine pulled me up the rest of the hill at a better pace.  I was near the top at that point anyway, and the rest of the way to the campground was uneventful.  When I got there I could see where some coolant had spilled from the overflow hose to the rear bumper.

The good news is going home is mostly downhill, but I am now thinking that my Radiator may be the culprit in this overheating issue.  I had just cleaned it before my last trip, but will probably clean it again and flush it as well.  I am also thinking about changing out the antifreeze.  Wanted it done anyway but was glad just to get the MH serviced since time is at a premium lately.

Does anyone else have a better plan of attack?  I have seen that Super Steer may have new radiators for this, but would rather use that as a last option.  Anything else besides the radiator that would cause this issue? My next planned trip is not until Sept, but I would really like to get this fixed before that trip.

Thanks

Oh bye the way wifi at this campground is really sketchy so it may be a few days until I can get back to anyone.  Took 3 tries to send this

[Steve Huber]

Carl,
What gears were you in when climbing? Did you  lock into the lower gears or did you allow it to upshift and downshift automatically? Also, did you have the "Economy" mode selected? What RPMs were you running when it was heating? You said you cleaned the radiator. Did you give it a good flushing and refill with fresh antifreeze?
Sorry for all the questions but cheaper than replacing a radiator which my not need it.
Steve

[Eric Maclean Co-Admin]

Carl
When climbing and the temp is getting out of control do you ever here the tell tail sound of the cooling fan spooling up
As discribed sounds like having an air plane in the engine compartment.

If not I be checking to see if the thermostatic control for the fan is working.
In our vintage coaches there where two types of thermostatic control system
The one my coach has is a rad hose electrical temperature switch that  controls a hydraulic solenoid which switches the hydralic motor high or low speed
The  other system uses a wax temperature control which hydraulically switches the fan motor high or low speed

Your coach is likely the wax temperature control
The way these systems work is as the temperature goes higher the valve closes which stops the hydralic flow through the by pass on the hydralic motor switch forceing the motor to run at full speed of the temp valve doesn't close you only get reduced cooling fan speed

Hope this helps
Eric

[Steve Huber]

Eric,
He has a rear radiator with a direct drive fan. No wax valve. That's why I'm so focused on RPM when climbing.
Steve

[Richard Davis]

Carl
If your coach is a rear radiator model, your problem may be simply reduced air flow thru the charge air cooler and radiator.  On my first rear radiator coach ('98 Tradewinds with CAT 3126), the cooling problems were primarily an accumulation of trash collected between the CAC and radiator.  It was difficult to clean out since there was no way to access that area.  By prying the fan shroud out and creating an opening of about 1/2 inch between the CAC and radiator, I was able to rake out a bucket full of leaves, candy wrappers and paper cups that had all gone thru the fan, over the CAC and fallen down blocking air flow to the radiator.  After removing all that "stuff" and then cleaning the radiator and CAC with Aircraft Simple Green, the air flow was much improved and no more overheat issues.  I would have mentioned this earlier, but I assumed (as Eric did), that you had a side radiator.  Best of luck with your issues.
Richard