Skip the auto shop - Our mechanics make house calls

Q: Random and seemingly instantaneous coolant leak after attempting to bleed the cooling system.

asked by on

I was given this vehicle because the previous owner did not want to pay to have it fixed. The car would run for about 20 minutes before overheating. I would prolong overheating by running the heater. I decided to troubleshoot the issue and decided that bleeding the system was a good idea and easiest to do. After this I planned on replacing the radiator cap with the same pressure rating because coolant escaped through the cap. After my obviously failed attempt at bleeding the system I drove the car and it began overheating much faster than it normally did. I parked and shut off the engine before it could actually overheat and after 10-15 minutes of waiting for the engine to cool off, I saw a large coolant leak. Also, the heater trick stopped working. What did I do to have caused such a seemingly random leak? The leak seemed to originate from the right side of the engine so it might be the water pump or it could have leaked out of the cap again. Any advice or tricks? Thanks.

My car has 150000 miles.
My car has an automatic transmission.

It would seem that there may be excessive pressure in the system for some reason. Because you replaced the cap and now presumably this is keeping a better seal on the coolant from coming out of the cap, it may be possible that this has forced a leak elsewhere in the system.

The other question would be what is it that is causing the excessive pressure? I would recommend checking the thermostat to be sure coolant is flowing properly. Also check to be sure the coolant fans are coming on as they should and that the relays do not need to be replaced.

If you need assistance with getting this fixed, consider YourMechanic, as one of our mobile technicians can come to your home and diagnose your overheating issue firsthand for an accurate repair.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Random and seemingly instantaneous coolant leak after attempting to bleed the cooling system.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Can my 2003 non-turbo 2.4 L engine be swapped into my 2004 turbo PT Cruiser?

Anything is possible, but it's not a straightforward swap. The powertrain control module (PCM) is different as is the wiring. I'm sure there are other subtle differences as well. You could use the 2003 as donor car and pull everything...

Q: Keep trying or get another

Buying a JDM car, whole - is not something easily done, since cars built for other markets don't necessarily meet U.S. crash and emissions standards. Unless it is a model sold here, it will require Federal DOT certification. You can...

Q: Power steering Leak

The leak sound like it is coming from the rack and pinion seals. A sealer will not work for power steering pressure leaks in most cases. You will need to have the system pressure tested and then the rack and...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...