The short answer
If the temperature gauge is climbing into the red or steam is appearing, pull over safely and shut the engine off — continued driving can warp the cylinder head within minutes and turn a $200 repair into an engine replacement. Let it cool 30+ minutes before even opening the hood, and never open a hot radiator cap.
Likely causes, ranked
- 01
Coolant loss from a leak
most commonA failed hose, water pump seal, radiator seam, or heater line lets coolant escape until there isn’t enough to carry heat away. The most common overheating cause — and usually visible as puddles or crust trails once on a lift.
- 02
Stuck thermostat
commonA thermostat stuck closed blocks coolant from reaching the radiator at all — classic rapid overheating shortly after startup. An inexpensive part with an expensive failure mode.
- 03
Cooling fan failure
commonIf the car only overheats in traffic — a Western Gateway Bridge backup, a drive-through line — but cools on the highway, the electric fan or its relay is the prime suspect. Airflow at speed masks the failure.
- 04
Failing water pump or head gasket
less commonA worn pump can’t circulate coolant; a breached head gasket lets combustion pressurize the cooling system. The head gasket is often the *result* of a prior overheat — which is exactly why stopping early matters.
What to do right now
- 1
Pull over and shut the engine off as soon as it’s safe. Heat blasting on full can buy a mile or two in a pinch, but stopping is the real answer.
- 2
Wait 30+ minutes before opening the hood; never open the radiator or reservoir cap while hot — pressurized coolant scalds.
- 3
If coolant is visibly low and you have the correct type (or water in an emergency), top off and drive gently and directly to a shop — or better, have it towed in. Call (518) 348-7764 so we know it’s coming.
What it typically costs
Diagnosed early: hoses and thermostats commonly $180–$420, radiators $600–$1,200. Driven hot: warped heads and head gaskets start around $1,500–$3,000 and climb toward engine replacement. The tow is always the bargain. For fleet accounts, a cooling-system pressure test is part of every spring PM for exactly this reason.
Our diagnosis fee goes toward the repair.
Related questions
Can I just keep adding coolant and drive it?
You’re refilling a leak on a timer you can’t see. It works until the day the loss rate wins — usually on the Thruway — and one bad overheat undoes years of careful maintenance.
A pressure test finds the leak for less than a summer’s worth of coolant jugs.
Why does my car only overheat in traffic?
At speed, ram air cools the radiator for free; sitting still, the electric fan has to do it. Overheats-in-traffic-only is the textbook signature of a failed fan, fan relay, or clogged radiator core — a targeted, findable problem.
What actually fixes it
If it turns out to need real work, this is what usually does it — with pricing published up front, so there are no surprises.
Same symptom on a work van or truck? Fleet units get priority bays and one monthly invoice. Fleet repair →
Still not sure how serious it is?
This guide describes common patterns, not a diagnosis of your specific vehicle — that takes an inspection. If your symptom is marked urgent, treat it as urgent. When in doubt, stop driving and call (518) 348-7764.
