Engine Overheats after Full Rebuild, but Why? (YOU WONT BELIEVE IT) 

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Can't blame the cat for catching a mouse 🙈😂

This is why as a mechanic as soon as you think you have seen it all, something comes along and proves you wrong!!

Thanks Josh, I should have brought it to you to begin with!

Thanks for the shout out Josh. Jerry caused this destruction. Tom finally had his revenge. Made me laugh. Great diagnosis video.

Wow, that's weird but makes sense. Worst animal versus engine one I heard to this point was a landfill compactor (Al-Jon), had a Cat C15/D398TA pre-DPF engine (its been 20+ years since it happened), and it had been parked overnight outside of the maintenance shop at the landfill after running the previous day. Early morning, Operator comes in and fires it up only to be startled by the immense amount of racket that occurred when it cranked over and fired up. Shut it down quick, but the damage was done. What happened? Somehow a stray cat (no pun intended) had crawled past the shields over the engine cooling fan/shroud, and met Mr. 600 HP Caterpillar radiator fan, and it had dismembered the feline and shattered the blades on the 6 foot diameter nylon fan blades. The blade remnants ended up piercing the radiator, and I felt sorry for the techs from our shop who had to go out to it, as they were picking out pieces of the furry culprit from the engine compartment for hours. Radiator, fan, reversing hub, and some of the shields had to be replaced. Reps from Al-Jon came out as they had thought they had it closed off well enough that Mr. Whiskers could not gain access to the void between the fan and radiator during shutdown. They came out and went over it and made improvements to the engine compartment so that it would not happen again. Ironically it was the only time that an animal had ever gained access to a space like that, even on the older Detroit 8v92 powered compactor machines that weren't as well protected as that new machine was. Needless to say, it was the most expensive Cat fight I had heard of up to that point.

This is the second time I have seen this exact problem. The last time I seen it was on a 1958 Ferrari that had been apart for a while. Apparently the mouse made a home in the radiator while it was in storage. When the customer reinstalled the radiator, the mouses home and his/her siblings/children met their demise at some point and clogged up parts of the cooling system!! One of the odder diagnosis I have been involved in during my years as a tech!

Wow- drives home the need to plug orifices with at least a shop towel when things remain open during repairs. Never hear of one of those getting in a cooling system before! Thanks for sharing Josh, love your videos.

I work for a large city municipality. we have a fleet of trash trucks. We have never found a mouse in side an engine but we have found them everywhere else. Mice and rats both in the trash bodies usually where the hyd leak is, that's right they chew through 5000 psi hyd hose.

Same with my cat in the Pete. Except it was a rag from a new pump install. I pulled it all apart on the highway, halfway between Edmonton and Grande Prairie Alberta, and thank goodness I had 12 bottles of coolant

Very interesting! Further reinforcement for capping open ports. We had a Cat come in with a mysterious overheat issue that turned out to be a blue shop towel in the oil cooler, coolent inlet...so along with plugging ports, make sure you remove everything...lol.

I feel very justified suddenly for always being OCD about blocking up every line/hose when I'm working on stuff, tho in my case it was just to keep out dust LOL!

Cat caught the mouse. Guess he wanted to leave this cruel world, just chose a bad way to do it. Either that or he liked his alcohol and had to much Ethyl. Good education on keeping openings covered and plugged when working on engines. Glad you did a video on it. Be safe Sir.

I love you josh. You'd be surprised how many animals mess with stuff out in the jobsites. One time we found a rattle snake and pieces in side the front diff of a Cat 657 scraper. One of the service guys left the dip out. The diff was over heating and we drained the oil. The oil was plugged up at the econo plug and we had to remove the trans and open the diff with all the oil in it. Found most of the snake in there all ripped up. We checked the axles and planetaries. Fun times. Love you josh (no homo)

Great lesson for anyone who does engine tear downs and rebuilds. Thank You for sharing! So glad I caught this video!

Thought it's the shop guy left a rag there, didn't expect the end result at all😂

Hi Josh I am a diesel engine mechanic here in Brazil. I always follow your videos, here we don't have Caterpillar in trucks, but we have in machines and industrial. Your explanations are very nice. Success to you.

Rats and mice do love the taste of coolant and screen wash. All ways clean any spilt on wires or engine off.

And that folks is why you keep things covered up till it’s time to install them. Always love what you are doing, and have learned a lot from you, like how to run overhead and how to remember the sequence

Thats crazy. I think about that occassionally with an open engine especially outside. Great vid

My dad has that same problem almost with the C15 in his truck. In 2021, the temperatures were rather high at about 210°. Then one night in Kingman he saw a small coolant leak but said it wasn't that bad and wouldn't do anything, the very next day, that same leak put us on the side of the road for 7 hours in the middle of nowhere, about 10-15 miles from Flagstaff if I remember correctly. Later that year, they had to put a new radiator in it I think for I don't remember the reason but it was all rusted out below from when they switched the coolant from the green stuff to the new red stuff. A few months ago, the engine was rebuilt and he said it still runs at about the same temperatures as it did before. But he said it still gets hot and he doesn't know why, he thinks it's a low flow water pump. I wish his company would send the truck up to your shop to take a look because their mechanics are just interns right now, then one quit a few days ago so it's just one now.

For AL G.RITHIM cuz I don't have much to say, but darn, you and ezrider,are my favorite diesel mechanics. Although he is more a driver than mech, his knowledge is amazing.

I saw something happen similar once on a 3306 TA in a D6D CAT on an in frame rebuild where a shop rag was waded up and left in the port between the aftercooler and head. Took a while to figure out, but just have to go through the troubleshooting process like you did! I guess kind of like a doctor forgetting his tools when he sew’s up the patient! Lol! Great video!

That's very kind of you to share it with us, most kind, from the endless summer paradise Puerto Rico, Jesús Torres.

My brother once stored his 1969 jaguar XKE in some one's garage for a period while he was assigned in the airforce to alaska. when he returned two years later and tried to start the car, he broke the crank shaft because some mouse had packed one of the cylinders full of dry dog food. the mouse simply climbed in the exhaust pipe and filled the cylinder after coming thru the exhaust pipe muffler the exhaust manifold and then thru the open valve. If i had not been there i would not believe this story either.

Awesome diagnoses! Really enjoy these videos, you really know your stuff. Thank you!

My daughter inherited a '69 SS el Camino that hadn't run in 23 years. Mice made the exhaust their home and peed on the #5 exhaust valve so much, it stuck open, broke off and took a massive chunk out of the cylinder wall of the 396. The Hooker headers were rusted out and They even made it through too the intake on one plane due to the valve overlap. I plug exhaust during long storage now!

It's always a good idea to use a little Decon additive in your coolant.

That is wild. I was having a conversation with my stepdad the other day about how a 3406 can pressurize the radiator but not blow a head gasket, he told me he think the space between the valves doesn’t have enough metal and an overheat situation makes hairline cracks on those heads, he has had to change a few heads already

I used to love getting difficult problems like this. It took the drudgery out of the week. Beats the hell out of doing the same jobs over and over. In the early '70s I think I changed the head gasket on every Chevy Vega every made.

Love these. Happens more than I would care to admit in water cooled systems with open recirculation

RIP Fievel!, he was well known to make nests in the engine compartment, but a baller move to try to move inside the block.

I had a similar problem with a brand new CAT 245 excavator that was shipped from the USA to SA Capetown .We unloaded the machine from the ship, loaded it on a lowboy,the radiator cap was missing ,while I was were unloading the machine in the yard I noticed that the water temperature was very very high.pulled it in the service bay and after a long while of testing and guessing as to what the proplem could be. We found pieces of a dead bird in the radiator hose .that was in 1978 and have never forgotten about it .

I work in Aviation A&P for 26 years . Good video in aviation you always cap and plug everything when you take things apart. GOOD REASON WHY .

Amazing the engine got as far as it did, without catastrophic failure.

That is so crazy. The zoom in at the end sent chills down my spine. It's like...a whole new genre of horror.

I'm working on 12 snowblowers currently and restoring a 79 Ariens to add to my collection. Out of the 13 machines, some maintained but most not, 9 were damaged by mice with some mice getting caught in sprockets and chains. Not exactly the funnest of jobs having to clean the transmissions out and replace broken chains but the little bastards put food on the table. One ate through a plastic fuel tank and overdosed on ethanol.

I did an out of frame a few years ago. put the truck back together and started it, very shortly after starting a very black squirl jumped out of the stack and ran out of the shop. it must have got in the exhuast while the truck was outside the shop while the engine was being rebuilt, and was in there when we put the motor in and hooked everything up.

Definitely one of the more bizarre problems I've heard of. Good catch!

A shop I worked at that had pretty poor housekeeping had some bundy tube, a roll of it, sitting around for years. One day I use it to make a brake line on a customer's car, could not get the line to bleed, no fluid through the line at all. Turns out that ants had got inside the tube, I mean lots of them, died inside it and turned into a solid ant mass blockage. Open ends invite creepy crawlies.

The old ethylene glycol coolant was an animal attractant. Many dogs died from drinking it. Maybe the newer stuff still has a sweet taste/smell.

That’s crazy! Who would ever guess? Very cool breakdown and explanation! Thanks!

Your videos are great man. I really enjoy what you share and how much you know. Thanks for posting!

Looks like the Cat ate the mouse... A great video..good teaching one to show the importance of keeping open holes plugged when apart for service...and to look your new parts over thoroughly.

Well done Columbo!! Enjoyed this vid👍

I knew exactly what that was when I seen you pull it. I have had that same issue on a Dodge truck, left the cap off and the mouse drown in the coolant reservoir. No heater for awhile, was very hard to clean out

Thanks for teaching me more about my engine. As always great video.

You can quickly get into really bad trouble with bad parts. Just like it happened to me. I had the water pump replaced in my 1983 Ford Capri with the 2.3 liter V6 engine. The first one was from SKF and made noises - exchanged - also made noises - exchanged... then another one from Hella was available. I have photo evidence on my website. The housing around the pump wheel was closed and either happened when the pump housing was cast or was not separated afterwards? In any case, the pump wheel could not transport water and the engine became too hot. We puzzled around for ages until we removed the water pump again and compared one pump with the other one... (End of song: We reinstalled the old water pump that I actually wanted to replace when rebuilding the engine, and it still works today). But you can now get such a step sold... it's unbelievable.

Great video A great example of best practices of covering/capping any hoses tubes open components during rebuild An alternate title dot the video might be A game of Cat and mouse !

That mouse seen that big block of yellow cheese and could not resist.

Now I have to say I have seen it all, I would have never guessed that in a long time. Thank you for sharing? Really though, thank you Sir.

I had to replace my water pump engine still getting hot well after the shop, last one in Nephi,Ut and the owner and everyone one was baffled, well oil cooler was plugged, the red and green coolant was mixed anyit plugged up the oil cooler, so pulling over parleys summit was a blast, it over heated going up the pass and when oil cooler was replaced no more over heating issues. Thank you for the video.

Wow! Wouldn't believe it if I hadn't seen it. Would love to have seen the customer's face when you showed/told him.

in my years of working on the 3406 PC TA's and A models i have seen two spun impelers one was split the other just spun, probabably from re-using the impeler to many times after a seal change

Great find. We learn something new every day.

Happens all the time in Wisconsin when the temperatures drop. Mice love to live inside your air and cabin filters. When I haul Trane components all the the hoses and air intakes are blocked off to stop creatures from building nests in them.

That was a good one. Mice and farm equipment do not mix. Love your work dude and thank you!

Wow that's so crazy another great video keep up the good work Sir you are very good at what you do

Oh man. Friggin mice. At first I thought it was a paper shop towel. I bought a 1990 F250 once that had sat for years. Mice made a nice cozy nest in the air filter box and intake hose and made a nice meal of of all the wires under the hood

Amazing work Columbo

Good find,great diagnosis,thankyou for the video.

Thanks for your time. You are very amazing BOSS

No sh.....?! A mouse????wtf! After 40 plus years of marine engineer work this is unf....in’ believable. Kudos to you 🎉

Proving once again that an adept ape shall overcome a cool mouse 🤣. Very interesting video👍

Well that was a twist ending. The whole video up to the mouse reveal I thought a mechanic left a rag inside.

I've never heard of that. But that will be on for the books.

You are the best thank you for sharing all your knowledge on all your other videos thank you very much take care and God bless

Years back I saw this in another "rebuild". A rag was left in the engine during the reassembly. Same symptom--overheating.

Gives a whole new meaning to we have a mouse in the house lol great video love your videos.

Seeing an animal in there, that's 100% new! I've seen this rust a time or two before after fresh rebuilds; Cause #1 is some mechanics filling up with just tap water only (that's OK, keep reading) just to get ALL the swarth & crud out, and make sure everything is working right before draining & dumping 15 gallons of coolant in the engine after the very first 1 or 2 heat cycles on water, yet don't get *all* of that tap water out and whatever's in the *tap water* reacts with metal & coolant for some very nasty compounds. Cause #2 is mixing tap water with concentrate rather than distilled I saw that mistake way more than anything else - suddenly thermostats aren't lasting very long, radiator cores crusting up and not cooling efficiently. Not near as bad as 100% water but still no good. I've seen a red shop rag completely wound around a water pump impeller before. Don't f*ck up cooling systems young mechanics, we all make that mistake at least once in our careers 😁

OH MY GOD, OF COURSE IT WAS A MOUSE! Civilized man's oldest adversary: the humble mouse. Gets into your grain, eats it, everybody dies. Gets into your wires, eats them, everything gets fried. HIDES OUT IN THE COOLING SYSTEM? Just... goddamn it. Nice "catch" Josh, looks like you've been promoted to chief mouser at Western States!

It reminds me of the Air Traffic Controllers joke. "You land 10,000 planes safely nobody remembers...have one small mid-air collision and nobody forgets". The odds of this are small and plugging every hose/hole during a rebuild aren't feasible. Good thing the engine was shut down before damage. We have all seen acorns in airboxes. That mouse had a bad day!

Back in my dim and distant past I had a weird overheating problem arrive at my workshop. It was on a Morris Marina with a 1300 A series engine. In slow moving traffic on a hot day it would run at normal temperature, but, out on the open road it would overheat, basically the opposite of what you would normally expect. After a bit of head scratching I made a discovery that I had to confirm with the customer. I asked if he had recently had an accident repair done, to confirm what I had found. He said yes he had slid into a gatepost on an icy bend and had the car towed to the main dealer for a front end rebuild and new radiator, waterpump and fan. The A series engine is fitted to a lot of different vehicles including the original Mini. I had noticed that the radiator grill was getting hot when it should have been in a stream of cold air. Turns out that the dealership had fitted a Mini fan that in its intended transverse engine vehicle pushes air from the engine bay out through the side mounted radiator into the wheelwell. In this inline engine it was, at speed, trying to force air against the incoming airstream, effectively preventing air from passing through the radiator. When moving slowly this wasn't an issue. I replaced the fan with the correct one and problem solved. We also gained a regular customer.

The Cat Columbo... Always gets his mouse....! Awesome.

Id like a video on the coolant liner band cavitation. The v series can happen. Ive seen some with inserts in the lower o rings area

Best I saw was a shop rag left in the lower radiator outlet. The cat dealer was not pleased. I used a diagnostic procedure they taught. ( Temperature differential between radiator inlet and outlet).Good times.

Had that problem before. The down line from the coolant tank the the pump inlet was stopped up at the tank fitting. The customer put 5 bottles of that ceramic sealer in the cooling system.

Wow 👌...Didn't See that Coming!..Great Video

*LOL!* a Cat caught a mouse! I'm sharing this with my friends in the trucking industry. man, there's just some things you can't fully prevent. it probably went after the shop rag for nesting material.

Years ago I had a mack r690 250 4 valve. I had a mack dealership shop install a new radiator (I didn't have time to do it myself). I picked the truck up, drove roughly 3 miles and the temperature gauge pegged. I took it right back. Whomever hooked up the bottom radiator hose didn't remove the rubber protective cap from the radiator. The cap was the kind that went over the radiator pipe stub. The guy had to fight to get the hose over the rubber cap to put the hose on. The guy must have been asleep, on drugs, or something.

When Freightliner stop working on Cat’s, I only trust Ring Power Cat in Riverview Fl to work on my C15 NSX. I had a terrible experience at Rush in Tampa.

When I was a parts manager for a foreign car dealership in Princeton I had a mechanic ask for an AMC water pump. We were a dealer for them to. I told him to be sure to read the instructions in the box. He went into a rant about how long he'd been a mechanic A little latter he was back ranting that the pump wasn't pumping Bring me the box! In the box were the instruction, still clean and folded. If you had rad the instructions you would have learned that the new pump has a bigger impeller, you needed to pull a head bolt, install the pump and then use the new bolt that's still in the bottom of the box. Same dealership ran stock car's, one day before a race at Trenton they rebuilt a Chevy V8. When they started it burnt rags were flying everywhere, they suspected they had left rags in the cylinders while the heads were off :( They pulled an all night pulling the heads only to find the side pipes were blowing out rags from under the bench the welder hadn't swept up :(

Wow, I was not expecting that one.

This has got to be one of the weirdest if not the weirdest vehicle problem I’ve ever heard of. On any vehicle ever! Crazy!!

A mouse! Excellent piece of detective work, sir!

CAT and Mouse , how ironic. Kinda like Tom and Jerry situation. Great pick-up mate.

Reminds me of a 3208 in a Ford Cargo that was brand new but had been in storage for about 2 years. It overheated horribly. When it was pulled apart to find out what had gone wrong it was found that EVERY coolant touching surface was lowered by ~20 thou (0.5mm). Not only that but the block was full of rust. The coolant had turned acidic for some reason over the storage period and attacked all of the iron (block and heads) eating it away perfectly.

That is one expensive mouse trap!! 😀

You got to be kitten me! This was a real game of cat and mouse troubleshooting this problem. Curios as to when the mouse got in there, guess the rad did not have caps on it to keep fod out of it. Will put that on my list to flush out the rad before installing to make sure no critters are in there.

Great vid/investigation 👍

That was interesting. I myself am fighting a heating issue. Not sure if it thermostats or water wheel, or just faulty temp sensors.

This shows that capping lines and hoses for contamination control is really important. Also, how do you meet flat rates while making videos? The cat dealer I work at skimps is on time pretty bad

I have saw plenty of fresh overhauls on Cats come back overheating most common cause is a rag was left in the lower radiator pipe water pump grinds it up and it plugs up the face of the oil cooler

Fun and informative video! Love these videos from the Ape!

Man I was expecting like a shop rag wedged into the coolant system but not a poor mouse. I guess that’s one way to get killed by a cat!

I've had issues with people added stop leak to the cooling system and causing the same issues

Thank you Josh

Wow...I wudda never thought that happen... BUT you never know.... GreaT VideO...!!!!

Haven't seen that yet but I sure can believe it!

I had a truck drained down and left the pan under the truck overnight. When I came in the next morning there was 6 dead mice floating in the coolant.