Tractorman

I am assuming the turbo whistle is a pleasing sound to your ears, not an annoying one. Which turbo model do you have? - John

All turbos should sound like this! Mine doesn't - I'm jealous! - John

Here's mine - owned it since new. - John

I never have taken any decibel readings. I have done small things over several years to tame some of the harsh sounds that the Cummins engine emits. My focus has been to do things that reduce the source of the sound. For example, I have not spent a lot of time and money in attempts to insulate the cabin from the noise of the engine because when you roll down the window or step outside, all of that engine noise is still there. Instead, I have tried to reduce the noise from the engine right at the engine itself. The valve cover and especially the oil pan act as speakers and really do transmit a lot of engine noise. The best material for insulating those items would contain some dense solid mass (like lead) to have the best results; however, the additional weight is usually not desirable, so we compromise. When I worked around heavy equipment in the high country of Colorado, I could hear that an idling 3208 Cat engine with an insulated oil pan was much quieter than one without it. I didn’t need a decibel meter to observe that. Adding Mopar1973man’s IAT resistor circuit reduced engine noise during cold weather (around 50 degrees and especially colder) by modifying engine timing. An excellent idea – thank you Mike. I made and installed a length of ribbed plastic 3” drain pipe inside the BHAF. This pipe reduced engine air intake noise in the same manner a muffler does. It also reduced exhaust brake noise that backfeeds into the intake side of the engine. It is the combination of these additions or modifications to the engine that have reduced the overall unwanted noise coming from the Cummins engine that I can’t live without. I can tell you that if my truck is parked by another 24 valve second generation truck and both engines are idling, my truck will be quieter inside and outside. Each modification or addition by itself offerd small benefits in engine noise reduction, but when added up, the difference was noticeable even without using decibel meter before and after. Probably the one thing I miss most now is the turbo whistle – it is gone, and it is the one sound I liked! John

I have a heat blanket covering the exhaust manifold, turbo charger (exhaust side), exhaust down pipe, oil pan, and valve cover. This heat blanket is designed to easily withstand temperatures well above 2,000 degrees F., so the material does not deteriorate. The heat blankets were custom made and installed by Advanced Thermal Products in Irvine, CA The engine compartment runs considerably cooler, the seals in the exhaust brake vacuum cylinder no longer get scorched, and the passenger side floor now stays cool when pulling a long grade on a hot day. My wife likes that. I also removed the homemade heat shield protecting the BHAF as it is no longer necessary. There are noise reduction benefits, as well. The raucous idle clatter is subdued when standing outside of the vehicle as well as when sitting inside or driving down the road with the windows up or down. My wife likes that, too. The purpose for covering the valve cover and oil pan was for engine noise reduction only. The purpose for covering the exhaust components was for heat reduction in the engine compartment. There was some noise reduction benefit, as well. I can't make any claims as to the turbo spooling faster or that it is more efficient, but the turbo performs well (spools up early) and EGT's stay under 1200 degrees on a long grade pulling hard. This is with stock injectors and the Smarty programmer set on SW5 with default timing and fuel duration. As far as turbo cool down, it is always below 350 degrees by the time I park the truck, so I don't treat the cool down period any differently than I did before the heat blanket installation.. I can't compare EGT before and after the exhaust blanket installation because I had the EGT gauge and Smarty installed after the exhaust blankets. The blankets have been in use for over 45,000 miles and over two years. In my opinion the benefits are worth the money. - John

I would go to the Blue Chip Diesel site for VP44 and other components diagnostic chart. There is very good information at this site. Also, you will want to confirm that batteries, battery connections, grounds, etc. are all in good operating condition. Others will chime in soon to help. - John

I have a shop heated with a wood stove and I work in it almost every day. The shop is considerably smaller than yours, but the idea is still the same. The shop is 36’ x 30’ with 14’ eve walls and a 17’ peak. There is also a 200 square foot room with a 10’ ceiling attached. The total shop area is just under 1300 square feet. The building is a pole barn style (girts and purlins) with metal roof and metal walls. For the ceiling (roof) insulation, I have R25 fiberglass batts placed between the 2 x 8 purlins (24” on center) covered with white plastic sheeting. For the walls, I contstructed 2 x 4 inner walls (16” on center) which provided space for 5 ½” fiberglass batts for insulation (the extra 1 ½ inches of space came from the width of the girts). I covered the wall studs with OSB sheeting so I could hang anything on the walls anywhere I wanted. I also installed a commercial ceiling fan about three feet down from the peak of the ceiling. The woodstove came from my house when I upgraded to a larger woodstove in the house. The woodstove in the shop is a Regency 2400 series with a 75,000 BTU capacity. I also live in the Pacific northwest (the Willamette Valley in western Oregon). I can tell you that on a day that barely makes the freezing mark, I can easily keep my shop at 70 degrees. The air is always dry, even when you walk in first thing in the morning. The ceiling fan is a must; I reduced my firewood use about one-third after I installed it. Also, the ceiling fan makes the temperature throughout the shop much more uniform. I know that you are trying to do something for the interim, but with the size of the building you have, I think I would put all my energy toward the final product. I think I would get the walls and ceiling to at least an R21 rating, otherwise the shop will be difficult to heat no matter which choice of heating source. If you use portable propane or kerosene heaters for the interim, you will be adding moisture to the air. That heated air with the added moisture will likely condense on objects far away from the source of heat. - John

I will be replacing mine very soon as a maintenance item - no sense in taking a chance for unnecessary damage. You must have treated your clutch right! I see by your signature that you have a six speed. What brand is your replacement clutch and how do you like it? - John

So far I have 288,000 miles on my original factory clutch. How many miles do you think you will get from your original factory dual mass flywheel? Sorry..., I just had to ask. Enjoy your new ride! Will you still help us out with questions about our ancient trucks? - John

13766-180HP. It must be the 180 horsepower alternator for the V6 Cummins 24 valve. - John

I have also wondered why I have not experienced some of the electrical problems that many others have. I bought my truck new and right away I put the grid heaters on a manual control switch. I very rarely use the heaters. And, like you, my alternator (a Bosch) has never given me trouble. I replaced brushes and bearings (only for maintenance, the alternator was working fine) three years ago at 216,000 miles. I am currently at 285,000 miles and the alternator passes your AC voltage test. I never tested for AC output until I came across your website and I will be keeping a close eye from now on. - John

That's the trouble with this site - lots of information tossed around about the beer, but no information of any value; like, where is the beer and who is bringing it? - John

I understand your dilemma here. If you replace a component and then recharge the system with refrigerant and it slowly leaks out, you will have three choices: go to an AC shop to recover the remaining refrigerant (the best solution, but costs money), wait for the remaining refrigerant to leak out (could be a long time), or intentionally dump the remaining refrigerant into the atmosphere (an environmental no-no). This same issue is what got me to start looking for a used R134A refrigerant recovery machine. I found a used Snap-on ECO 134 A for $650. It came with a new 30 lb tank full of R134A and a 20 lb recovery tank, lots of AC parts, seals, gaskets, tools, etc. This particular machine recovers, filters, and recharges refrigerant. It has a very accurate digital scale that measures refrigerant in ounces for recovery and recharging purposes. It is capable of collecting and releasing non-condensable gases and has an oil separator. It also comes with a vacuum pump for removing non-condensable gases, moisture, and for performing the leak test. When I was looking for a recovery machine I actually ran across two of this specific model Snap-on machine - the second one went for $250 (it had no extras). So, there are good used recovery machines out there and they cost a lot less than I expected. For me the refrigerant recovery machine has given me peace of mind because I now do not have to worry about the high cost of repairs and I can keep all of my vehicles charged with the proper amount of refrigerant at the beginning of each summer season. - John

How many miles on the AC components, especially the compressor? Last spring I had some of the same concerns that you had. I knew I had a refrigerant leak, but I didn't have any means to find it. I ended up buying a used Snapon 134A recovery machine at a reasonable price. Since my truck had the original Denso AC compressor still on it with over 260,000 miles, I decided to change it out with a new Denso unit. I then pulled a vacuum on the system; it passed the test so I recharged the system with 30 oz of refrigerant. I drove the truck for 600 miles and then recovered the refrigerant. I pulled out 30 oz, so I knew I had found the leak. Later, this fall I replaced the heater core. Again, I recovered 30 oz of refrigerant confirming that I had found the leak. When I replaced the heater core, I did not replace the evaporator core because it looked to be in very good condition. Time will tell whether or not I made a good decision. So, if you have high mileage on an original compressor, I would start there. The condenser would be the next likely place if it has never been protected by a screen. I believe that the o-ring connections on all of the line fittings are pretty reliable since there are two o-rings on each fitting. I have read that some people have had evaporator core failures. I would suspect these failures could be from some rubbing in the housing or from debris packing into the core since the evaporator core is the first place unfiltered air comes into contact with after passing through the blower fan. - John

Since you just installed the engine, I would check all air intake connections for the charge air circuit for boost leaks from the turbocharger outlet to the air intake plenum on the engine. - John

Excellent write-up! ... and complete with photos and wrench sizes. I know that I will have to address this at some point in time due to the age and miles on my truck. This is the kind of information owners of older trucks need to help keep repair costs down. Thank you. - John

It is true - there is no horizontal adjustment. My guess is that there has been some minor body damage on the left front side or right front side of your vehicle and that damage has misaligned one of your headlights. With your low beams on at night, can you tell which headlight is aimed correctly and which one is out of whack? It is likely that only one headlight is the problem. When you make this check, do it when it is not foggy. Thick fog can distort what you see. First make sure that you have the correct bulbs and that they are installed properly. Then inspect the area around each headlight to see if any of the headlight fixture's fasteners are loose, out of place, bent, broken, or missing. Worst case scenario is that you may have to take some things apart and reshape some body parts to correct the alignment. - John

I did do something similar back in 1988. I wanted a pickup or a van with a diesel engine and I became very frustrated at the choices available at the time. Choices like a heavy V8 engine, no turbocharger (really!), three speed transmission, all accompanied with lots of noise, smoke, high rpms and … no power! Just what I wanted. So, in the spring of 1988 I purchased a new Cummins 4BTA engine kit and put the engine in my 1984 Ford E150 van with a factory 4 spd manual overdrive transmission. I drove with this configuration for 87,000 miles (by then I had 212,000 on the vehicle). I lived in Leadville, Colorado (elevation 10,000 ft) at the time. With the Cummins engine, I could drive up a 7% grade at 65 mph in overdrive, and still accelerate! And no smoke! I was a happy camper. The van had two factory fuel tanks, one 18 gallons, the other 22 gallons. On one occasion after driving back and forth from home to work for a week (50 mile round trip) and then going on vacation traveling on top of the Grand Mesa pulling a small trailer with two ATV’s, I drove just over 1,000 miles without refueling. I netted just over 29 mpg on that fill-up. In 1991 I bought a new Ford F150 Extended Cab 4X4 and immediately swapped in the Cummins engine. Everybody thought I was nuts. I drove that truck for over 200,000 miles and then sold it. I kept fuel logs for over 100,000 miles of driving. The overall fuel mileage for the first 100,000 miles ( which including all driving and idling) averaged out to 22.5 mpg. It was a great engine! My next vehicle was a new 1999 Dodge with a Cummins. Somebody finally did it right! - John

My 6 spd manual transmission locks up in every gear, even reverse! However, it is very annoying the way you have to unlock it - you can't just flip a switch. If you don't unlock it during shifts, it makes grinding noises. - John

Here is a different way to look at it. Let's say the truck is going down a grade at 1700 rpm's with the torque converter locked up, no throttle input from the operator, and the truck's speed is being held constant with just the friction of the engine being forced to run at that rpm (the drag). If the torque converter is switched to unlock, the engine rpm's will fall immediately, not increase. The falling engine rpm will reduce engine braking. The truck will begin to accelerate. I have no experience with Toyota transmission controls, but I am guessing that there is more going on than just unlocking the torque converter. - John

IBMobile and I are saying the same thing. I hope we are not being included in the "you guys have it wrong" part. - John

I know that the automatic transmission does not shift into neutral when coasting, but it gives a similar sensation when the converter unlocks. Is it possible that you are feeling a programmed downshift when the brake is tapped in the circumstance you described? I believe that transmissions that have the "Tow / Haul" feature will automatically downshift on a downgrade when the brake is tapped if the "Tow / Haul" feature is turned on. In this case the converter will unlock during shift but locks up again after the shift and it is the lower gear that you feel holding you back. - John

Try this scenario. Pretend you are climbing a grade with a load using 5th gear in a 6 spd manual transmission. You crest the top of the hill and begin descending the other side. You like the feel of the engine holding you back a little.. You approach a curve and need just a touch of brakes to help maintain your speed. Would you shift the transmission into neutral at this time? I don't thinks so. If you were driving the same scenario with an automatic transmission in 3rd gear (OD locked out) with the torque converter locked up, then you would not want it to unlock the converter when you stepped on the brake. It would be kind of like putting the transmission in neutral. - John

I just realized that I gave you wrong information. I had it in my head that we were talking about a second generation truck. You are correct - on your truck the fan is controlled by the ECU, either when the engine temperature is high enough, or when the AC head pressure reaches around 250 psi. With that said, a different but similar situation could be occurring. If you have your ventilation setting in the defrost mode, the AC compressor will be cycling by default. With very little air flow through the AC condenser, the ECU could be telling the fan to come on because refrigerant pressure has increased significantly. It could be a combination of both engine temperature and AC head pressure. I apologize for the confusion on my part. - John

Possibly what is going on is that you have disrupted the engineered smooth, laminar air flow through the AC condenser core, CAC core, and radiator core . If very little air can enter the fan intake area, then very little air can leave the fan exit area so the temperature in that immediate area may rise fairly quickly and the thermo-sensor in the center of the fan hub will engage the fan. Once the fan is fully engaged, it will generate a considerable amount of turbulence and air recirculation because its air intake supply has been essentially cut off. The engine would not have to be "hot" for this to occur and the fan may run for some time. Without a winter front installed the thermal sensor in the center of the fan hub always has a smooth stream of air flowing across it - so it is very stable and engages the fan with repeated accuracy when necessary. What you could try is to have at least four separate openings in your winter front. They should be equal in size and be evenly spaced around the perimeter of the winter front area. The idea is to have several places for air to pass through without creating turbulence and to also have enough air flow to keep up with the fan speed when it is disengaged (the fan is always moving some air) If you get it right, then the thermo sensor will always have a stream of air passing around it. Some of the better winter fronts on the big rigs are set up like this. - John