Loud squealing and excessive coolant pressure

RLC3ISME

MEMBER
2003 MAZDA PROTEGE
80,000 MILES

Starts after much effort, runs rough and at high rpms, then dies. The squealing sound is coming from the throttle body area (not specifically the throttle body). I just replaced the head gasket, head bolts, and all gaskets nessesary when reassembling.

Deck and head surfaces were withing flatness specifications. Timing was reset to factory. Ignition is a little weak but sufficient and fuel delivery is good. This problem completely baffles me and is disappointing with the experience I have and a run performance certification. I know its difficult to diagnosis without seeing the car, but all help is appreciated.

9 Replies

KHLOW2008

MECHANIC
41,815 POSTS

First you need to do is to locate the source of the noise. Throttle body can only be air noise which would squeal if an air passage has a leak or there are restrictions to it.

Ensure the cooling system has been bled of air trapped in system and if the high pressure continues, it would mean the head job has a problem somewhere.

If the reason for replacing the head gasket was due to overheating, the head seems to be the one at fault, or at least it is related to it.

Were the valve clearances checked/adjusted?

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Friday, September 7th, 2012 AT 1:32 AM

RLC3ISME

MEMBER
5 POSTS

Thank you for the quick response. The original problem was coolant leakage into cylinder but once it warms up it went away. Also cylinder to cylinder leakage. Valve clearances and actuation was fine when the head was off. Definitely did not check for the air in the coolant system, too busy over thinking everything I guess. Now that I think about it the throttle body gasket had slits covering (maybe) vacuum passages.

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Friday, September 7th, 2012 AT 1:55 AM

KHLOW2008