Skip the auto shop - Our mechanics make house calls

Q: Swollen coolant water pump bypass hose

asked by on

I have a coolant hose that I need help identifying. It comes from the bottom of the thermostat and appears to go into the block. The problem I have is the hose swole enough to strike a bolt close by and puncture it. I haven't had any cooling issues lately, but I did recently "fix" a leak I couldn't find by using some sort of cooling system stop leak.

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

The small hose that comes from the bottom of the thermostat housing and has a small bend then goes straight down into the top of the water pump is called the water pump bypass hose. This is the hose you wanted to be identified. If you had a coolant leak and it stopped when you used the stop leak is most likely coming from the thermostat housing. The thermostat housing is made from plastic with rubber O-rings to seal in the coolant. The housings are known to crack and start leaking coolant. You would need to replace the thermostat housing assembly to stop the leak.

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
  1. Home
  2. Questions
  3. Swollen coolant water pump bypass hose

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: Engine is over heating and I'm not getting heat. 2001 Pontiac Grand Am 3.4 V6

Hello - I agree with your diagnosis - a water pump failure is a prime candidate for both overheating and a "no heat from the heater". Lack of water flow will cause both symptoms, and cause damage to the engine...

Q: Coolant shooting from passenger side of the water pump

When you had the water pump replaced the surface on the engine block most likely did not have all the old gasket material removed. I would recommend having the water pump replaced and both surfaces cleaned thoroughly by a mechanic...

Q: I just bought a this used car two weeks ago. The radiator seam split.

With regard to the cooling system, if the vehicle was professionally inspected prior to sale, such would generally cover visible leaks, low coolant level, obviously rotted hoses, gross corrosion on the exterior metal surfaces of the radiator, visible tank cracks,...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.