Why do I see so many excavator videos on youtube with the engine bonnet open?

[thebaz]

I am curious to find out the reason why so many excavators in youtube videos have the bonnet open. I have seen this very rarely in Australia and have never had reason to do this myself, so I would love to know the reason if there is one as to why the bonnet needs to be open while operating.

 

[pp13bnos]

Chances are the machine is running on the warm side.

 

[thebaz]

Chances are the machine is running on the warm side.

Yeah, I thought that would be the case, but it seems to be so common in these videos. I have worked in 40c heat and never had the bonnet open.
Would it make much difference bonnet open to bonnet closed to engine cooling?

 

[Nige]

Personal experience - yes.
TBH on the larger machines the airflow through the engine compartment is, shall we say, "convoluted". Couple that with a big turbo and things get hot pretty quickly.
We had a lot of success opening the hoods on a fleet of 349's where I currently work. Rather than run with the hoods permanently open, when we could see that the experiment worked we ended up removing them altogether. Last time I saw them they were lying in a heap in the bone yard.

 

[John C.]

In truth most excavators only have enough cooling capacity for 100 degrees F and everything working properly. Put some dust in the radiators, maybe loosen the fan belts and turn the screws up to make the hydraulics work a little faster and you will have heating problems.

We also used to punch holes in the side doors.

I thought the 349 had the extra hydraulic oil cooler and hydraulically driven fan?

 

[Mannie]

Overheating I guess

 

[alrman]

Most machines that are designed to be sold in Australia (through mainstream dealerships) have had their cooling systems upgraded with lager capacity radiators - with more rows of cores or tubes in them.
Any machines that are imported into the country via auctions (from Europe or Asia) usually have a smaller radiator core fitted to them.
Well, that's my experience with Case Equipment & many smaller imported excavators I have seen.
So, like @John C. says, you only need a small percentage of air flow restriction to cause them to overheat - especially in extreme temperatures.
Hence, they try to get better air flow by opening the bonnets....

 

[245dlc]

I have run at least two different series of JD excavators where cooling was a constant problem. Both the 200CLC and the 200DLC had the Deere engine and had excellent power and speed but were terrible for overheating even in cooler weather despite having clean rad's and being in good mechanical shape. It got so bad on the 'C' we had removed the doors and the engine hood without much improvement in performance. I was told maybe a few months to a year later the reason could be that the fuel was turned down so much that it was starving the engine causing it to overheat. Whether or not that's true I don't know. However I do know that the equivalent Hitachi which had a 4 cylinder Isuzu as opposed to the 6 cylinder Deere John never had this issue and also consumed a lot less fuel. I recall some Cat 320 excavators like B and C series machines would overheat but it was largely because Cat didn't put enough cooling louvres in the body panel doors. I think eventually the final 'C' series machines had more louvres in the radiator compartment making it better for cooling.

 

[Volvomad]

Manufacturers design and build some very good machines only to make foolish mistakes . On cooling alone , including agricultural machines , some have grills that are too small in area or too coarse to block trash ,some have restricted air flow ,under sized rads or oil coolers , no room to clean in between coolers in packs ,over stretched under designed fan drives ,thermostats that fall apart and jam them selves or their mate shut and aluminium rads designed to block internally . I have only ever worked on one small mixed bag of gear for my 22 year slog and I have removed/modified bonnets sometimes blocking part of air intake area to redirect more air to side or top mounted oil coolers, drill thermostats to increase water flow ,and plenty more .30 C is extreme over here .I am ranting again .

 

[td25c]

Open up all the doors & winder's in hot weather . Helps keep man and machine a little cooler .

Plus I like the smell of that pond muck but don't tell anyone I said that .

 

[92U 3406]

Old fella I worked with up north mentioned to me one time that opening up the doors on an Hitachi was a bad idea as it made the overheat problem worse. He said it is always the foam seals around the coolers. Either missing or leaking. This fella had a couple decades in with the Hitachi dealer so I do trust his knowledge.

 

[StanRUS]

Personal experience - yes.
TBH on the larger machines the airflow through the engine compartment is, shall we say, "convoluted". Couple that with a big turbo and things get hot pretty quickly.

345C, muffler air cleaner extractor elbow cracks and hot gases melt hydraulic tubing starting fire. $60K plus to repair and 5 weeks out of service. Dealer said nine 345Cs in the area had burned.

 

[KRIZ]

I found on two small hitachi's i ran (135ur) that previous "fitters" had removed bits around the cooling package which let the hot air from the engine side of the pack recirc back around.... All because two bolts were hard to get to. Differences in thermostat crack and fully open set points is a major factor with import non dealer ship machines as well. The other issue is air cleaner integrity a choked up air cleaner while not bringing on a restriction alarm can raise engine temps as well. There are tropical conversions that have different pulley dimensions and larger air cleaner units to help ( Doosan). I agree with Stan designers seem to run out of smarts when it gets to environmental operating differences for their latest creations just look at air con designs in diggers .... some are truly pathetic in performance and serviceability.

 

[Nige]

Comparing how things were done yesteryear (generally well over-sized) and now (on the limit) it's all down to one word - money........
It's cheaper to build it as small as you possibly can, and f**k the customer.