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GMC Coolant Questions

GMC coolant leaks can happen without warning and if not repaired quickly can cause a vehicle to overheat. Not only can this leave the driver stranded, it can cause serious engine damage. Loss of coolant without any visible signs of leakage is also possible. Finding the cause of the GMC coolant loss and getting the right repairs done can be difficult. The insights and guidance of Experts will help owners get their cooling system problems fixed in the right manner.

Read below where Experts have answered questions about GMC coolant.

What will cause a GMC Sierra C2500 to spray GMC coolant out of the overflow pipe when under heavy load but not when driven on the highway and the engine does not overheat?

It is unlikely that the problem is caused by the EGR or thermostat. If it is an EGR issue the coolant would leak out, not spray and if it is a thermostat problem, there should be overheating. The problem is likely the head gaskets, front and rear, which need to be replaced. This is a fairly common issue with this vehicle.

Does the intake and head gasket need replaced on a 1999 Suburban when the GMC coolant is leaking from rear most passenger side intake bolt under the edge of the intake?

A leak at this position is fairly common on this vehicle. In most cases only the intake gasket is leaking and will need to be replaced. Replacing the intake gasket takes between 4 to 6 hours of labor. Replacing the head gaskets takes about 14 hours and if the heads are taken off they will need to be pressure tested and a valve job may need to be done at a machine shop. Generally speaking, replacing the intake should fix the problem.

Is it normal for GCM coolant to be seen in the air chamber of the intake manifold of a 1998 Sierra?

A small amount of oil in the air chamber is normal, but there should not be any sign of coolant. The coolant is probably leaking past the intake bolts because of a failing intake lower gasket. Replacing the gasket should fix the problem.

Is it normal for GMC coolant to be leaking from a small hose on the passenger side of the engine?

The pipe described sounds like the drain from the air conditioning system evaporator in the dashboard. Water draining from here is normal, but not coolant. The fact that the coolant is leaking form here indicates that the heater core is bad and needs to be replaced.

Will the block heater in a 2005 Envoy Denali leak GMC coolant from under the engine near the oil pan and filter?

In many cold regions engines may have block heaters that fit into the frost plug holes in the side of the engine block. These are to help in cold starts. They can develop leaks and result in coolant draining from the area mentioned. Though it is not common, frost plugs themselves can leak. Also unusual but possible is that a coolant leak in another area drips onto a wiring harness and the liquid flows along the casing covering the harness to emerge at a point away from the actual leak itself. The cylinder head gaskets are located low on the engine block. Leaks from here are rare, but the possibility cannot be ignored. The best way to determine the location of the leak is to have a pressure test of the cooling system done and look for leaks after placing the vehicle on a hoist.

Overheating is a major cause of engine damage. GMC coolant problems should be attended to as soon as they are noticed to prevent the possibility of time consuming and expensive repairs. If the repairs are not done correctly the problems may become worse. Obtaining professional help when dealing with GMC coolant problems is the best way to ensure the right repairs are done. The guidance and answers of Experts is the best source for this information.
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