Cooling system repair in West Chester

If the temperature warning comes on

Stop when it is safe and switch the engine off. An aluminum engine driven hot can warp its cylinder head within minutes, and a hose that would have cost a little becomes an engine repair. A low coolant message is the early version of the same warning: the coolant went somewhere, and topping it up does not tell you where.

What fails

The water pump is the repair we do most often on BMW, Audi and Volkswagen. The usual list:

• Water pumps. Many BMW six-cylinders have an electric pump that stops without warning. Volkswagen and Audi four-cylinders have a plastic pump-and-thermostat housing that seeps, then leaks. Belt-driven pumps weep at the shaft seal first.
• Thermostats. Stuck open, the engine never reaches temperature: a weak heater, worse fuel economy and a check-engine light. Stuck closed, it overheats.
• Radiators and expansion tanks. The plastic end tanks and seams crack with age and heat.
• Hoses and plastic pipes. The plastic coolant pipes on Jaguar and Land Rover V6 and V8 engines, the nylon lines on Mercedes-Benz, the coolant flange at the back of Audi and Volkswagen cylinder heads, the coolant lines to a BMW's turbocharger. They turn brittle and split at a seam.
• The cooling fan. Fine on the highway, hot in traffic.

How we find the leak

A cooling system pressure test is a quick diagnosis at a set price. We pressurize the system and the cap and look where the coolant comes out — cold, and again hot if it only leaks hot. Coolant that disappears with no drip gets tested for the other possibility: that it is going into the engine.

The estimate lists what is leaking and what is about to. If the water pump is out and the thermostat beside it is the same age and the same plastic, we say so: the labor overlaps, and the coolant is being drained anyway.

Coolant service

• How often. Our schedule is every 60,000 miles, or your maker's interval where that is shorter. The additives that stop corrosion wear out long before the coolant stops protecting against frost.
• Tested at every visit. The coolant's level and freeze point are part of the bumper-to-bumper inspection.
• The right type. Each maker specifies its own coolant chemistry. We fill with that one; mixing types shortens the life of both.
• Bled properly. European systems trap air easily. The system is filled and bled by the maker's procedure — on many BMWs that means running the electric pump's own bleed cycle — so no air pocket is left to cause the next overheat.

When we replace a water pump, a thermostat or a radiator, new coolant is part of that job.

Cooling system questions

Can I just keep topping it up?

For a few days, with the right coolant, to get it to us. Not as a plan: a leak that is slow today lets go on a hot day in traffic, and plain water in a European engine starts corrosion and freezes in winter.

My car loses coolant but I never see a drip. Where is it going?

Either onto something hot enough to boil it off before it reaches the ground, or into the engine. A pressure test tells the two apart.

Why replace the thermostat with the water pump?

On many engines they sit together, are the same age and take the same labor to reach. Doing both once costs less than doing the second one a year later.

Is a coolant flush the same as a coolant service?

We drain the old coolant, refill with the type your engine is specified for and bleed the system. What matters is the right coolant in and the air out.