Engine overheating problem started three weeks ago?

Tiny
BRITTMASIE4
  • MEMBER
  • 2016 VOLKSWAGEN TIGUAN
  • 2.0L
  • 4 CYL
  • TURBO
  • 2WD
  • AUTOMATIC
  • 138,100 MILES
My vehicle listed above overheating problem started three weeks ago. I have replaced the thermostat, coolant temperature sensor, cooling tube assembly, mass airflow sensor, flushed coolant, checked fuses, fans are running. There are no leaks anywhere at all. The water pump was just replaced less than one year ago. I am at a loss here. The car has had a #4 miss fire code for many months now but has always still run and currently still does. I have changed the plugs and coils twice now. Code still shows #4 miss fire along with a check engine light. When I turn the car on, I can drive the car in 90-degree summer heat for about 10 minutes. It does not overheat when idling, it overheats on the highway for about 3 minutes in. Especially on hills and climbs. When I slow down on the highway the temperature starts to return to normal. I also turn the heat on max high to help the temp return to as close to normal as possible. When I get to a red light or come to a stop, the temperature starts to slowly drop back down to normal which is 190. I am so completely stumped on what this could be. I cannot afford a mechanic, and my warranty has run out, unfortunately. I would appreciate your reply so much! Thank you.
Friday, July 25th, 2025 AT 11:59 PM

6 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,144 POSTS
It sounds like you have a blown head gasket which will cause the #4 engine cylinder to misfire. Here is a guide to help you run the blown head gasket test, start by draining a small amount of coolant out as to not containment the chemical fluid.

https://www.youtube.com/watch?v=5zpNjYmmiYY

Also, check the front of the radiator fins to make sure they are not filled up with dirt or mud. It might be worth going over this guide as well:

https://www.2carpros.com/articles/engine-overheating-or-running-hot

Please upload pictures or videos in your response.
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Sunday, July 27th, 2025 AT 11:14 AM
Tiny
BRITTMASIE4
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I watched the videos you sent. I tried to use my vacuum gauge to check some things today and I had a friend come over with a better OBDII reader and these codes popped up today. I just changed the mass airflow sensor. So, could it be that I need a new crankshaft sensor or camshaft sensor according to the codes? I can't keep throwing money at this and I am very limited now. Wouldn't a blown head gasket throw a code? Unfortunately, since my car has been inoperable for over three weeks, I am very limited due to not being able to work. I use my car for work. No stores around me have head gasket dye kits and I can't wait for Amazon to deliver it in a few days. I need this fixed as soon as possible. While having the OBDII reader plugged in with the car engine on, it read the engine coolant temperature at 214 and when I turned the heater on max high the temperature. Went down to 195-198 while doing live feed on the reader. I need to try and fix this ASAP. What are your thoughts? Have they changed at all?
I very much appreciate your replies.
Thank you
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Sunday, July 27th, 2025 AT 7:49 PM
Tiny
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  • MEMBER
  • 4 POSTS
Also, I forgot to add, when I tried using my vacuum gauge, the only port I could find on my engine was the throttle body vacuum port and my gauge reads 30inhg, the highest it can get on the gauge. I'm wondering if this is normal.
Thank you
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Sunday, July 27th, 2025 AT 7:52 PM
Tiny
KEN L
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Yep, that sounds normal, there is no code for a blown head gasket, but if it was blown then the spark plug will be much cleaner than the rest. Looking at these codes it seems you have more than one problem. When it starts running hot do you hear the radiator fan come on? Please start a new thread for the codes. We only handle one problem per thread, please post your new question here, you must be logged in.

https://www.2carpros.com/questions/new
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Monday, July 28th, 2025 AT 12:16 PM
Tiny
BRITTMASIE4
  • MEMBER
  • 4 POSTS
The spark plugs all have carbon buildup on them and they are all the same. I actually drove the car for work today. I can go much further down the highway in early morning hours (4-am-630am) and it won't overheat until about 10-15 minutes within those hours on the highway. Today when I drove it from 345am-745am I had to do some highway and a lot of start and stop. I noticed that when I do start and stops the temperature. It is normal and as long as I do back roads and side streets the car stays normal temperature for pretty long. On the highway if I go above 50-55mph the temp. Starts to climb within 10 minutes as I was saying. However, since I had to work. I figured out that when the temperature starts to climb and is having trouble coming back down (after sun comes up) I learned that if I pull over every 10 minutes and open my reservoir coolant cap to let pressure out for a minute or two and continue driving it helps a lot and returns the temp. Back to normal and allows me to go further. I did this about 20 times today while working and made it home. (I was sent 40 minutes away from home and took all back roads) If I do not do this, the reservoir will be almost full and boiling in about 15-20 minutes. I don't know why taking the cap off is helping so much? In the sun, if I pour a half gallon-gallon of water over the radiator and closed cap reservoir it also brings the cars temperature to normal almost immediately. To answer your question, yes. The fans are coming on when it is hot.
Just to give you an idea of my job- I work for amazon and use my own car to deliver packages if that makes a little more sense on why I have to start and stop so much and sometimes am forced to get onto highway if I can't do back roads. The fans do come on when hot and when I cool the radiator off with room temperature water the fans slow down and eventually turn off.
Any advice at all is much appreciated! I can't thank you enough. I'm just so stumped on this.
I will make another thread for the other things.
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Monday, July 28th, 2025 AT 12:55 PM
Tiny
KEN L
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Thank you, it can be a slight head gasket leak or a clogged radiator either internally or externally. These are the only options left, so I would do the test and if it comes back negative change out the radiator.
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Monday, July 28th, 2025 AT 1:36 PM

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