95 mustang leaking coolant behind water pump.

Coolant Leaking Behind Waterpump

95 mustang v6 leaking coolant behind the new water pump. worse when turned on. does not appear to be the pump or any hoses.

Solution:

If the leak is behind the water pump , then either the new water pump gasket is leaking or the timing cover from the timing chain that the water pump bolts to is leaking and the gasket between the timing cover and the engine block.

A couple of the water pump bolts are actually studs that go through the timing cover to the engine block. When the nuts are loosened, the timing cover also loosens. If the gasket for the timing cover is close to failing, it will start to leak. The reason it doesn't leak much with the engine off it because the water pump is not running and no real pressure is on the system. When the engine is running, the cooling system builds up pressure, usually 16 psi and it will push through a weak gasket.

I think it is just in need of a new gasket at 151000 miles. The bolts will really go in one way and the nuts on the studs will tighten up when in the correct place. If you removed the studs, then the gasket is in need of replacement.

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PROBLEM 2:

Now it idles smooth. Seems to have all the air out of the coolant lines. BUT when I drive it, it runs with the temp gauge to the red, then cools off to the center, then back to almost the red. The only time the heat kicks out hot air (heat on the whole time) is when it gets to the red and immediately goes to the center. At this time, it runs rough. After it cools off, it idles great, runs great for a short while. Think it is a head gasket?

There should be a bleeder cap bolt located on top of the engine near the front of the intake.It is right above the thermostat on the intake manifold.

There should be a bleeder cap bolt located on top of the engine near the front of the intake.It is right above the thermostat on the intake manifold.

graphic

When the engine is cold, remove the bleeder bolt and fill the radiator with coolant till the coolant comes out the bleeder opening. Then reinstall the bleeder bolt and start the engine. Let it warm up and then loosen the bleeder bolt, do not remove it, just loosen it and let some coolant come out and then close the bleeder. Top the coolant off and drive the Mustang.

The problem you have is an air pocket in the cooling system.

Thermostat Operation:

The automotive thermostat is a temperature controlled on and off valve. When the temperature rises to a predetermined temperature, the thermostat opens up to allow the engine coolant to flow through the cylinder block and the radiator. This flow is crucial to maintain optimum operating temperature for fuel efficiency, enhanced driveability, and engine protection. The coolant flow is reduced when the engine is cold, and the flow is increased when the engine is hot. Contrary to popular opinion, operating the vehicle without the thermostat doesn't make the engine run cooler. It will actually run hotter because there isn't a thermostat to slow the coolant flow. This means the coolant doesn't stay in the radiator long enough to dissipate its heat.

Coolant Temperature Sensor Operation:

This sensor monitors the temperature of the engine and sends that information to the engine control computer to regulate the amount of fuel needed. More fuel is needed if the engine is cold; less if it's hot. If the temperature is extreme, the signal will be sent to the temperature gauge as a visual indicator of overheating and imminent danger.

Chevy Water Pump Leak

Water Pump Leak Repair

I have a problem with a water pump leak. I have replaced the original with a new pump, but I still have a leak I suspect around the gasket between the waterpump and the engine block. Any suggestions? I was very careful to clean the surfaces and evenly tighten the six bolts in a rotation first finger tight, then to 11 ft-lb, and finally to 22 ft-lb. Is 22 ft-lb the right final torque or do I need to re-torque after the engine has been through a couple of temperature cycles?

Solution:

I would check the intake gasket for leaking and running down,looking like its the waterpump, as far as I can tell you are doing everything right ,if need be I would put a pressure tester on the cooling system and pump it to 20 lbs and looking very closely at the intake.

all I can suggest is to put a little sealant on the bolts,11ft lbs the first pass and 22 ft lbs final pass is the correct specs.no I wouldnt torque it to 28 ft lbs as you are asking ,.let me ask this,Is the coolant leaking in the same spot with the new pump as it was with the original pump?I would inspect it more closely as the heads bolt to the block right there and it may be that the head gasket is leaking (,just a suggestion) If it is leaking in the same spot or there is apparent leakage where the head joins the block,check for the head gasket,it seems that there was a problem with some of the heads on these motors ,...guy..

Bulletin No.: 06-06-01-019B

Date: June 12, 2007

INFORMATION

Subject:

Information on Gradual Coolant Loss Over Time With No Evidence of Leak Found

 

Models:

2004-2006 Buick Rainier

2001-2006 Cadillac Escalade Models

2001-2006 Chevrolet Avalanche, Blazer, Silverado, Suburban, Tahoe, TrailBlazer Models

2001-2006 GMC Envoy, Jimmy, Sierra, Yukon Models

2001-2004 Oldsmobile Bravada

2005-2006 Saab 9-7X

 

with 4.8L or 5.3L VORTEC(R) GEN III, GEN IV V8 Engine (VINs V, T, M, B, Z - RPOs LR4, LM7, LH6, L33, L59)

Supercede:

This bulletin is being revised to include engine RPO L59. Please discard Corporate Bulletin Number 06-06-01-019A (Section 06 - Engine/Propulsion System).

Some vehicles may experience a gradual coolant loss over time. A very low percentage of cylinder head(s) manufactured with an embossed Castech logo may develop a porosity crack in a very specific area.

Inspect the cylinder head assembly to determine if the casting was manufactured by Castech. This can be accomplished by inspecting for their casting logo located on top of the intake port, under the rocker arm support rail and in the spring deck cavity portion of the cylinder head.

If the cylinder head(s) are Not a Castech casting, follow normal diagnostic procedures in SI to determine the cause of the coolant loss

it could be that the head has cracks and that may be causing the head to leak near the waterpump,

if all of this does not show any leak then perhaps get another pump

I will always use form-a-gasket on waterpump bolts,just put a tiny bit on the thread near the end of the bolt,the thread in the block sometimes goes into the water chambers(depth),also I was just working on a chevy with the 5.3liter motor and looking closely at where the head joins at the block and it is very close to where the waterpump bolts to, also too ,the intakes leak on quite a few of these motors ,so check very closely 

Water Pump Gasket Operation:

Normally a flexible material that's placed between the water pump and engine block to prevent external coolant leaks. Certain styles of water pumps require a backing plate gasket to seal off access to the impeller and shaft assembly.

To replace a water pump gasket:

Remove the water pump. clean all remnants of the old gasket off of the engine. be careful not to gouge aluminum parts.

A water pump often has a steel plate bolted to its back. The plate gasket sometimes dries out during shipping. If this happens the bolts will be loose, causing a leak.

Before installing a new pump, it is a good idea to remove the bolts and cement both sides of the plate gasket.

When replacing a pump, be sure that all gasket material is thoroughly removed and that any o-rings, hoses, or gaskets are not damaged or forced during assembly. Be sure that the screws that hold the cover on the back of the pump are tight.

Use sealer to glue the gasket to the water pump. Sometimes a chemical gasket is used.

Be sure that the surfaces of the pump and block have been cleaned of all oil and coolant so that the chemical can stick.

Paper gaskets are generally the only gaskets, other than retorqueable head gaskets, that require the use of a sealer. Paper gaskets are found on timing covers, water pumps, water outlets, fuel pumps, and some carburetors. Several manufacturers make tool sets for cutting the holes in paper gaskets.

When replacing a damaged gasket, gasket paper can be purchased in sheets. A gasket can be roughed out by holding the paper against the part and tapping on it with a ball-peen hammer.