Since some of you are into Hondas and we all like to trouble-shoot car problems, here's a weird one that I ran into over 20 years ago with my 1998 Acura Integra GS-R. I'll write the symptoms and see if you can guess the cause and the fix, and then later I'll post the answer.
1998 Acura Integra GS-R
1.8L VTEC DOHC 170 HP engine inline 4-cylinder
5 Speed Manual Transmission
Front wheel drive
TL;DR
Acura Integra GS-R has wheel bearing replaced, next time on the highway there is a lot of heat emanating from the transmission tunnel, then the stereo head unit falls out.
Multiple thermometers show that the temperature at steering wheel level is 80°F but, when going over 60 MPH, the temperature rises to more than 130°F near the transmission tunnel between the seats.
The Acura dealership that replaced the wheel bearing under warranty reluctantly assigns a mechanic to investigate the symptoms and admits the intern who was helping with the wheel bearing removed the stereo head unit and did not reconnect it. The same mechanic, who at first could not find the heat problem, comes along for a drive and was shown that the temperature reading changed when the vehicle speed increased to 60, but he claims they're normal and refuses to investigate further.
When I told the symptoms to my friend, he meditated for two minutes and then crawled under the car with a flat head screwdriver and fixed the problem quickly.
LONG VERSION
I'd had the car for more than four years and knew how it performed under all weather and road conditions, which was perfectly, never running hot or cold from -25°F to 110°F. And suddenly one day, when I was distracted by my girlfriend and hit a hellatious pothole at low speed, the right front wheel bearing was toast.
The Integra was still under warranty, so I took it to the local Acura dealer where the service manager was friendly and helpful, and they replaced the bad bearing just before a week-long trip to the mountains for some car camping and day hiking with my girl and her dog.
It was the middle of the summer in one of the northern climes of the USA and, along the highway to the mountains, I noticed the car interior was much hotter than usual, even with the A/C on full blast, and it seemed like the heat was emanating from the transmission tunnel between the seats.
The next thing to go wrong was that on the dirt road to the campsite the stereo head unit completely fell out of the dashboard! In replacing and securing it with a piece of thick paper from a candy box, I noticed the head unit also had a deep scratch that was new and which I was certain could not have happened when it had fallen onto the gear shift boot.
When I returned to the city, I grabbed my Radio Shack indoor/outdoor, dual display thermometer that shows the temps from both sensors simultaneously, as well as a digital thermometer for HVAC pros that I used to confirm each of the other two readings. I hung one sensor in the air at steering wheel level and the other in the air near the transmission tunnel between the two front seats.
With the A/C on full blast and the ambient temp. around 85°F, the upper sensor read 80°F inside the car, which seemed a few degrees high, and the lower one was reading in the 130°'s. As I drove around, I discovered that the higher temps near the transmission tunnel began to increase with a very mild upward transition at 45 MPH, and then suddenly peaked once I hit 60 MPH.
I returned to the dealership and reported the problems to the same service manager, who was immediately incredulous about everything, especially the stereo, which he refused to inspect. He wanted to know if I had an alarm and if someone had tried to break in, so I told him I had a great alarm that had never been triggered and there was no evidence of a break-in. He continued to resist my request for service to this new problem that I said must have been caused by the wheel bearing repair, so I just kept repeating the symptoms and showing him my thermometers until he finally called a mechanic, to whom I explained everything again.
The mechanic agreed to look at the car and get back to me, which he did a day later, saying that he reconnected the head unit. He told me that an intern helper had disconnected the radio because he thought the wheel bearing job required it, and apparently he hadn't screwed everything back in. However, the mechanic couldn't find a problem with heat from the floor board, so I came over with my thermometers and we took a ride together in order for me to show him.
He was patient about driving at low and then high speeds and I showed him the readings, but he continued to deny the problem, so we switched places so that he could "operate" the thermometers himself. When he saw the readings and finally accepted them, he just said those were normal, so I asked if we could take the Integra they'd given me while mine was in the shop, but he refused and became unresponsive as I drove back to the dealership.
Failing to get help from the dealership, I was feeling vanquished and, in my frustration, I came too close to a parked pick-up truck with extended mirrors and knocked mine into his, causing the passenger mirror housing to swivel backward so violently that, when it reached its stop, the mirror lens popped out. Fortunately my passenger window was down and the mirror landed harmlessly in the seat and the housing wasn't even badly scratched. I tried for a few minutes to replace the lens, but I couldn't do it without feeling like I was about to break something, so I gave up.
Jarred back into reality, I suddenly remembered a friend who worked nearby and was mechanically gifted. His father was a major gear head and his son had inherited his skill partly from nature and partly from nurture. I found my buddy in his cubicle, wearing a suit and tie, and repairing a laptop. I told him my car had a problem just to see if he was interested and he immediately sprang up and came outside, where I explained all the symptoms. He closed his eyes and became still for almost two minutes until a large smile came across his face, then his eyes opened and he asked me for a flat head screwdriver, which I gave him as he crawled under my GS-R, not even bothering to remove his jacket.
I heard him underneath for a few minutes grunting and struggling with something and then he emerged with the same huge smile, his clothes perfectly clean and orderly, and he declared problem solved. Next, he noticed the mirror in my seat and I told him what happened, so he walked over, grabbed the lens and began massaging it back into the housing. In less than 10 seconds, it was good as new.
So what was the cause of the heat and how did my friend fix it?