After driving for about five minutes, it goes up past hot?

Tiny
TONI ALEXANDER
  • MEMBER
  • 2004 BUICK CENTURY
  • 67,000 MILES
Two elements: First, the temperature gauge was below Cold. After driving for about 5 minutes, it goes up past Hot. I have the heater at maximum, but it is blowing cold air on me. The second element is that the car loses acceleration. I was going 70 MPH but it began to slow down even when I pushed the accelerator all the way down. I couldn't get it to go faster than 50 MPH. The car has had this problem twice. I've taken it to my fantastic mechanic twice and he was not able to figure out what the problem was. He uses fancy diagnostic equipment and tried other stuff with no results. The other part of the story is that when I got to my destination all 3 times and sat through a meeting for about an hour and a half, when I went to drive home, the car behaved like a brand-new car. Go figure! A real puzzle!
Tuesday, February 4th, 2025 AT 4:18 PM

8 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Hello Toni,

We only handle one problem per thread so please start a new question for the "it to go faster than 50 MPH." problem. We will handle the temperature gauge problem on this thread. Wait until the engine has cooled down completely then open the radiator cap to check the coolant level, it sounds like it is low, and you may have a leak. This video should help:

https://www.youtube.com/watch?v=GSE9skKnOgY&t

If the coolant is super low, please go over this guide as well:

https://www.2carpros.com/articles/car-is-leaking-coolant

Please go over these guides and get back to us.

Was this
answer
helpful?
Yes
No
Wednesday, February 5th, 2025 AT 9:02 AM
Tiny
STEVE W.
  • MECHANIC
  • 15,233 POSTS
Does the loss of power coincide with the temp gauge rising or does the temp go up and then it takes a bit for it to slow down? Asking because it could be low coolant, but I would think the shop checked that. The high temp could also make the engine go into a default mode like the limp home on newer cars. So, as Ken said, check the coolant level in the radiator, not just the overflow canister. If that is okay then about the only way to figure it out would be to wait until it acts up and drive it straight to that shop, don't shut it off. It sounds like it doesn't set codes so unless they can work on it when it's "broke" it would be very difficult to say exactly what is wrong. It could even be fuel related, low fuel pressure could make it run lean and get hot, then the engine loses power because it isn't getting enough fuel. Again, it would be hard to test if it cures itself after setting. Have you ever tried turning the key off and restarting it when this happens? Did it make any difference, or does it only reset if it sets a while?
Was this
answer
helpful?
Yes
No
+2
Wednesday, February 5th, 2025 AT 11:20 AM
Tiny
TONI ALEXANDER
  • MEMBER
  • 4 POSTS
The coolant is full. My mechanic will look at it on Friday and I will share your suggestions. If this happens again I will try to turn the key off and back on again and see if that makes a difference.
Was this
answer
helpful?
Yes
No
Wednesday, February 5th, 2025 AT 11:53 AM
Tiny
STEVE W.
  • MECHANIC
  • 15,233 POSTS
I'm wondering if the power cycle with the key would reset the system and return it to normal. If it did then it would point at an electronic issue and not something that has to cool off like the parking 3 hours would do. Maybe something will show up at the shop this time.
Was this
answer
helpful?
Yes
No
Wednesday, February 5th, 2025 AT 7:59 PM
Tiny
TONI ALEXANDER
  • MEMBER
  • 4 POSTS
My mechanic suggested when acceleration slows to pull over, turn off engine and restart. I did that on the freeway, the car accelerated quickly and then slowed down. I tried it later when I was at a stoplight, and it didn't restart at all. The 3rd time it did start but slowly.
I had my friend whose son is a auto performance expert. His suggestion was one of 2 things" Water pump impeller stops working and not getting coolant or a thermostat problem.
Was this
answer
helpful?
Yes
No
Monday, February 10th, 2025 AT 10:32 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Yes, either of these items can cause this issue, I would try the thermostat first which has a higher failure rate. This guide will help you step by step with the instructions for your car in the images below.

https://www.2carpros.com/articles/replace-thermostat

Check out the images (below). Please let us know what happens.
Images (Click to make bigger)
Thumb
Thumb
Thumb
Thumb
Was this
answer
helpful?
Yes
No
Monday, February 10th, 2025 AT 10:41 AM
Tiny
STEVE W.
  • MECHANIC
  • 15,233 POSTS
HMM, so you shut it off and then on restart it worked OK for a bit, then it started again. Might want to have the shop test the coolant temp sensor as well. If it is acting up you could get the same results with the engine slowing down when the PCM thinks it's hot even if it actually isn't.
Was this
answer
helpful?
Yes
No
-1
Monday, February 10th, 2025 AT 4:23 PM

Please login or register to post a reply.

Related Engine Low Power Content

Fix an Engine with Low Power!
VIDEO
Fix an Engine with Low Power!
Instructional repair video
Symptoms of Low Engine Power
GUIDE
Symptoms of Low Engine Power
The power your car's engine is producing is important. When you step on the gas you need your car to accelerate, mainly to keep you out of trouble when getting onto the...
VIEW MORE