When I picked up my dozer (1965 D7E), I was assured that all fluids and filters were recently changed. With this in mind, I was surprised when my ol' girl suddenly started belching black smoke from the exhaust. The drop in power was so bad, she could hardly get out her own way. I thought that I had lost my turbo, so I parked her to let her cool down. Once cool, I removed the exhaust stack and stuck my hand in to examine the turbine wheel (if you need to do this, cover your hand first with a plastic bag - ask me how I know). The turbine seemed to be intact, it moved freely and it didn't have any excess play. So unless the fuel injector pump was all of a sudden injecting twice the fuel needed, I figured that there was something wrong with the air intake. I removed the bottom of the filter canister to get access to the element. What I encountered was this: These nuts are not accessible with a socket (too close to the side wall of the recess). I had to remove the entire filter canister to get the nuts off, using a pair of lineman pliers and beating the metal of the filter out of the way. This was the filter that came out: Note that the filter paper used to be white. Compare the old filter with a new one - one that took me ten days to find - below: With the filter attachment being what it was, I can see why somebody would skip the changing of the filter, even though the should not have. I replaced the nuts with a homemade version of the original hardware (I made four of them):
Here is the new filter installed in the filter canister: Now I have a filter restriction indicator that seems to operate just fine. I removed it and looked at the orifice and saw this: It looks like someone sealed it shut with a weld. Here's the inside: Can anyone think of a reason to permanently seal off the indicator? Does the indicator flutter, or make noise while in use?
I can see no reason why anyone would want to seal off a filter indicator. An indicator should not flutter, nor make any noise, they're a simple spring-operated device whereby the warning indication is pulled into view against spring pressure, when the intake vacuum reaches a pre-set level. Did the old filter have a date on it? Every air filter I've seen has a date on it, but if the date tag was originally just a decal or sticker, it may have fallen off. Be aware that no filter manufacturer - and this includes Caterpillar - will warrant their air filters for any longer than 12 mths from the date of manufacture. And the filter media in air filters degrades over time, and will eventually let fine dust through - especially if the filters have been washed clean before. Don't ask how I know this, it was an expensive lesson, the result was a "dusted" engine.
And you believed them.? Sorry but that ranks up there with "trust me, I'm a salesman" and "your check's in the mail"...... It's hard to see in your photos but was there a secondary element inside the primary.? There should have been one. It should have maybe 6 studs on it and fix into the filter housing with the nuts on the back side. If there was a secondary element what sort of condition was it in.? It should have looked like new if the primary element was doing its job. I have seen instances before where if a primary element got damp it could produce the black smoke symptoms you experienced. Was the old element significantly heavier (like double or more) than the new one.? Me neither. If you touch the weld with a grinder maybe you can remove that tack and open up the passage again. Might have to drill through it from the outside to completely open up the port. Sometimes the nipple connecting the indicator to the flange will have a screen in it (it looks like wire wool but is made out of brass) to reduce the possibility that any pulses in the air intake will affect the reading of the indicator.
There is no secondary air filter. It is the assembly below. The old filter was dry and the weight wasn't noticeably different from the new. I started the engine with the entire cleaner assy off the machine and it once again ran well with no black smoke, so I assumed that there was a problem with the element. The day that this occurred, I had just installed a working water temp gauge and it was indicating an overheating engine. I shut it down when the indicator hit 210F (how long has THIS been a problem). I used an infrared thermometer to sample various points on the cooling system and it seems to indicate that the regulators are not opening properly. I'm hoping that it is just a thermostat problem and have ordered a pair to replace this weekend. If the new pair don't fix the overheating issue, then I'll have to flush the cooling system. No, but I checked all the fluids and they were clean and new looking. I didn't check the air filter because, hey, I have an "air flow problem" indicator!
That seems weird to me. A filter shouldn't plug so fast between one day and the next so that the engine doesn't produce black smoke one day but does a day later. As the Chinaman would say - Sum Ting Wong.
When I examined the fuel system, I noticed fuel in the area around the filter. I also noticed that the fuel bleeding valve was open. I closed the valve, but not before things started operating normally.
I never found that I could trust those air cleaner gauges.I even fit new ones a few times,and they allways registered fine. Back in the day,you coukd blow them out once a day and was probably doing more harm than good. These days,mine get blown out 6 times max as per the book and thrown away ever year
I agree with Nige seems strange that all of a sudden it did that
The discolouration of the old filter and the intake pipe appear to indicate water has been in there, creating corrosion. Is there any way any water could have got into the air filter body? Did the power loss and black smoke start very suddenly (i.e., within seconds or minutes?) - or did it occur over several hours? I'm trying to envisage what circumstances would lead to a very large and substantial reduction in airflow, and the only thing I can think of, is a quantity of rusty water gathering in the pan on the bottom of the air cleaner, then being sucked up into the pleats of the filter media.
Loss of power occurred rather abruptly - probably within minutes. The air filter body was dry. When it happened, I noticed that the temp was around 210F. I was dragging downed trees up a hill with a chain when it lost its power. I just opened up the regulator housing and there aren't any, so I am pretty sure that they aren't sticking. There is also a fair amount of sediment in the area (the only place I opened up), so I'm going to have to flush the cooling system. I'm not sure that the overheating and the loss of power are related, but the loss of power issue has gone dormant. I've got a shop-vac and a generator on site, so I'll be using those to pull the sediment out of the system. If it is mostly rusty metal, then possibly an acid flush won't be necessary, but if there is considerable lime, then maybe it will be necessary. Is there a coolant drain valve on this beast? The parts manual and the service manual don't show one. What is the best way to flush the system?
Maybe the restriction indicator was damaged or if it was remote the hose was damaged so instead of fixing it properly they welded the port for it up. Maybe they were worried it could damaged or leak is another thought.
I used to throw away the restriction indicators on fire trucks(pumpers) because i found one that had a hole burned in the filter from ingesting hot embers. A restrictor will not be of any use in that situation, so the removal was done to keep firefighters from thinking/worrying about stuff they know nothing about. Its not like they would notice it anyway
There is a coolant drain, it is shown in the Operation & Maintenance manual, it will be located on the bottom radiator tank, or the inlet pipe to the engine from the bottom tank. Quite often there's an access hole in the side of the guard under the radiator. The tap usually takes a 9/16" socket, you use a couple of long 1/2" extensions to unscrew it from outside the guard. Weak acids make the best cooling system cleaners, but you must be careful, because thin radiator tubes can be damaged by harsh acid cleaners, in particular the ones that aren't choosy about the material they attack. A weak (2%-3%) hydrochloric (muriatic) acid solution is very effective, but it's quite a harsh acid and it attacks all metals, including the good base metals, which you want to avoid. If using hydrochloric acid, don't leave it in the system for an extended period, or it will damage radiator tubes and base metals in the system. It is good for attacking scale, and scale is the bane of cooling systems, it prevents heat transfer on a staggering scale. Cat claim even a 1/16" layer of scale reduces heat transfer by 40%. My preference for cooling system cleaners is for more benign acids, I use citric acid at about 2%-3% solution, because its safe (no need to wear gloves or eye and skin protection), and because it doesn't attack the base metals, nor aluminium, copper, or brass. You can add a chelating agent to your cooling system cleaner which will promote the dissolving of scale, which assists the citric acid, and speeds up the cleaning process. A typical chelating agent is EDTA (Ethylenediaminetetraacetic acid), which is exceptionally effective at rust removal. It's much more expensive than citric acid, but you don't need a lot of it. You can leave the citric acid solution in the cooling system for an extended period (up to several days) and it won't damage anything. Once you're satisfied the cooling system has been cleaned up, flush twice with clean water, and then refill with a good brand name coolant that contains rust inhibitors plus anti-freeze, if you live in an area where low temperatures are regularly encountered.
I found all the drain holes. The manual recommends oxalic acid for the internal cleaning of the cooling system. Would you go with the oxalic acid over the citric acid? Is there a reason that you chose the citric acid? I'm thinking that I will obtain both and give the system a full flush with each of the acids. I'm pretty sure that I'm going to need a super human effort to get the crap cleared out of the system. I'm afraid to use a HCl flush just because of the age of the machine - the last thing I need are pin holes in the jacket somewhere. I can't get the acids locally, so Amazon will be my friend for them. I'm afraid that I'm going to have to pull the radiator for a proper and thorough cleaning of the channels. I'll start her up tomorrow and get her to temp and use my infrared thermometer to examine the outside of the radiator for cold spots (indicating a blocked channel). I'm wondering if anyone has ever pulled just the top of the radiator off in situ (just thinking out loud).
IMO and experience, citric acid is the more effective of the two acids when it comes to rust removal. I believe this is because it contains more oxygen molecules than oxalic acid. It's not that hard to pull the radiator in one complete section, you should be able to lift it straight up and out, IIRC.