# Cooling System and Radiator Repair

> Overheating or losing coolant? We pressure-test the cooling system, find the leak, and fix radiators, thermostats and water pumps. Call or book today.

Source: https://goodyearelitetireupland.com/services/cooling-system-radiator/  
Last updated: 2026-09-22  
Business: Goodyear Elite Tire Upland, 1775 W Foothill Blvd, Upland, CA 91786, (909) 608-7699

**TL;DR:** When the **temperature gauge climbs** or coolant disappears, we **pressure-test** the system, check the fans and thermostat, and quote the repair before refilling with the **correct coolant**.

The cooling system moves coolant through the engine and radiator to keep operating temperature steady. Overheating usually traces to a leak, a stuck thermostat, a failed fan, a weak water pump or a clogged radiator. We pressure-test the system, inspect each part, quote the repair in writing, and refill with the coolant type your engine specifies.

## What should you do if the engine starts overheating?

Turn off the AC and turn the heater to full hot with the fan on high. That pulls some heat away from the engine. If the gauge keeps climbing or a warning light comes on, pull over where it is safe and shut the engine off. Never open a hot radiator cap; the coolant is under pressure and can burn you.

Driving an overheating engine can warp the cylinder head or blow the head gasket, which turns a hose or thermostat repair into a much larger one. Once the engine is off, call (909) 608-7699. We will help you decide whether it is safe to drive a short distance after it cools, or whether a tow makes more sense.

Inland summer traffic is where weak cooling systems show up first: long idles, high outside temperatures, and the AC running hard all at once.

## What usually causes overheating and coolant loss?

Most overheating comes from one of a handful of causes. Leaks lower the coolant level. A thermostat stuck closed blocks flow to the radiator. A failed electric fan leaves the engine hot at idle. A worn water pump stops moving coolant well. A radiator clogged inside or blocked outside cannot shed heat.

| Symptom | Likely places to look |
|---|---|
| Hot only in traffic, fine on the freeway | Cooling fan, fan relay, blocked radiator fins |
| Hot on the freeway, fine around town | Clogged radiator, weak water pump |
| Gauge swings up and down | Low coolant, air pocket, sticking thermostat |
| Coolant level drops, no visible drip | Heater core, head gasket, small leak that evaporates |
| Sweet smell, wet spots under the front | Hose, radiator, water pump seal |
| Heater blows cold while the engine is hot | Very low coolant or an air pocket |
| Gauge stays low, weak heat | Thermostat stuck open |

Hoses and the belt that may drive your water pump are covered on our [belts, hoses and timing belt](https://goodyearelitetireupland.com/services/belts-hoses-timing-belt/) page.

## How do we find a cooling system problem?

We start with a pressure test. A tester pressurizes the cold system to the rating stamped on the radiator or reservoir cap, commonly 13 to 16 psi, so leaks show up as drips or a falling gauge. We test the cap against that same number, watch the fans come on, confirm the thermostat opens (most engine thermostats open in the 195 to 205 F range), and look at coolant condition. For suspected head gasket leaks, we test for combustion gases in the coolant.

The inspection covers:
- Radiator core, tanks and fins
- Upper, lower and heater hoses plus clamps
- Water pump weep hole and pulley play
- Thermostat housing and gasket
- Cooling fan motors, relays and shrouds
- Radiator cap, tested against the pressure rating stamped on it
- Coolant level, color and contamination
- Overflow reservoir for cracks

Findings and photos go into your inspection, and the estimate separates the repair from optional items like a coolant exchange that is not yet due.

## Does the type of coolant matter?

Yes. Coolants use different additive chemistries, and manufacturers specify one for a reason. Mixing types can reduce corrosion protection and, in some cases, form sludge. Color is not a reliable guide, because brands use different dyes. We check the specification for your engine and mix it as the maker calls for, usually 50/50 with water, which protects to roughly 34 degrees below zero Fahrenheit and raises the boiling point above what plain water reaches.

Coolant also wears out. Its corrosion inhibitors deplete with time, which is why manufacturers list a replacement interval. Old coolant can eat at water pumps, radiators and heater cores from the inside. Our [filters and fluids](https://goodyearelitetireupland.com/services/filters-fluids/) page explains how we decide whether a fluid is due.

## Does towing change what the cooling system needs?

Towing raises engine and transmission temperatures, especially on long grades in hot weather. A cooling system that is fine for daily driving can fall behind with a trailer attached. Before a towing trip, have the coolant level and condition, fans, hoses and radiator checked, and watch the gauge on long climbs.

If you plan to tow a rental trailer, pair a cooling check with the [hitch and tow package inspection](https://goodyearelitetireupland.com/services/hitch-tow-package-inspection/). Trucks that tow regularly are covered on our [towing and hauling vehicles](https://goodyearelitetireupland.com/vehicles/towing-hauling/) page.

## Which cooling system warning signs can you check yourself?

You can catch most cooling problems early with a look at the overflow reservoir, the ground under the front of the car, and the temperature gauge. Check only when the engine is cold. A level that keeps dropping, a sweet smell after driving, or a gauge that sits higher than it used to are all reasons to book a pressure test before summer traffic finds the weak spot.

A quick cold-engine checklist:
- **Reservoir level:** it should sit between the marks on the overflow tank. Do not open the radiator cap.
- **Puddles:** coolant is usually green, orange, pink, blue or yellow and feels slightly slick. Clear water with no smell near the front passenger side is usually normal AC drainage.
- **Smell:** a sweet, syrupy odor after a drive often means coolant is hitting hot parts.
- **Steam:** any steam from under the hood means pull over and shut the engine off.
- **Heater output:** weak heat on a warm engine can mean low coolant or an air pocket.
- **Gauge habit:** learn where the needle normally sits. A change from that spot matters more than the number.
- **Crusty residue:** white, green or pink crust on hoses, the radiator or the water pump shows a slow leak that dries before it drips.

Write down what you saw and when. That detail shortens the testing.

## What cooling system mistakes turn small repairs into big ones?

The expensive mistakes are driving on after the gauge climbs, adding water for months instead of fixing a leak, and replacing a thermostat without finding out why the engine overheated. Each one lets a hose or seal repair grow into head gasket or engine damage. A pressure test and a clear repair plan cost far less than that.

| Mistake | What it leads to | What to do instead |
|---|---|---|
| Opening a hot radiator cap | Burns from pressurized coolant | Wait until the engine is cold |
| Water only, long term | Lower boil protection, internal corrosion | Use the coolant your engine specifies |
| Mixing coolant types | Reduced protection, possible sludge | Match the specification |
| Pouring in stop-leak | Can clog radiator and heater core passages | Find and repair the leak |
| Thermostat swap as a guess | Real cause (fan, pump, leak) remains | Test before replacing |
| Skipping the air bleed | Hot spots, false gauge readings | Bleed per the service procedure |

### How cooling connects to other work
- The water pump on many engines is driven by the timing belt, so the two jobs often share labor. The belt interval comes from the maker's schedule for your engine, not from a general rule.
- The electric fans that cool the radiator also cool the AC condenser. Air conditioning is charged by weight, and the refrigerant type and charge weight are printed on the under-hood label; see [air conditioning service](https://goodyearelitetireupland.com/services/air-conditioning-service/).
- Coolant temperature and thermostat faults can turn on the check engine light, which our [check engine light diagnostics](https://goodyearelitetireupland.com/services/check-engine-light-diagnostics/) page covers.
- Stop-and-go miles on Foothill Blvd and long climbs in summer heat push a tired system hardest, so a check before the hot months is worth the visit.

## Needed now versus can wait

### Needed now
- Temperature gauge reaching the red or a hot-engine warning
- Coolant leak that lowers the level between visits
- Cooling fan not turning on at temperature
- Coolant mixed with oil or signs of combustion gas

### Can wait
- Coolant exchange that is near but not past its interval
- Replacing an aging radiator cap during other work
- Cleaning bugs and debris from radiator fins
- Replacing a discolored overflow reservoir with no cracks

## Our process

1. **Hear when it runs hot:** Traffic, freeway, towing or all the time: the pattern points to the likely cause.
2. **Pressure test:** We pressurize the cold system and test the cap to find leaks.
3. **Component checks:** We check fans, thermostat, water pump and coolant condition, and test for combustion gas if needed.
4. **Photos and written quote:** You see the leak or failed part and approve the repair in writing.
5. **Repair and bleed:** We replace approved parts, refill with the specified coolant, and bleed out air pockets.
6. **Heat cycle test:** We run the engine to full temperature, watch the fans cycle, and recheck for leaks.

## What's included

- Cooling system pressure test
- Radiator cap test
- Cooling fan operation check
- Hose, clamp and water pump inspection
- Coolant type and condition check
- Photo inspection and written estimate
- Air bleed and heat cycle test after repair

## Frequently asked questions

### Can you flush my coolant?

Yes. We check your engine specification and the coolant condition first. A tester reads the freeze protection level, and the replacement interval comes from your maintenance schedule rather than a general rule. If it is due or tests weak, we replace it with the matching type and bleed the air out of the system. If it is not due, we tell you that too.

### Is it safe to drive if my car is overheating?

No. Pull over, shut the engine off, and let it cool. Driving an overheating engine can warp the head or damage the head gasket. Call (909) 608-7699 to decide between a short drive after cooling and a tow.

### Why does my car only overheat in traffic?

At speed, air flows through the radiator on its own. In traffic, the engine depends on the cooling fan. A failed fan, relay or blocked radiator fins often shows up only at idle. We check fan operation as part of the test.

### Can I just add water to the radiator?

In an emergency, water can get you to a shop once the engine has cooled. It dilutes the coolant, lowering boil protection and corrosion protection, so the system should be corrected with the specified coolant soon after.

### What color is coolant supposed to be?

Coolant comes in several colors, including green, orange, pink, blue and yellow, and color alone does not tell you the type. The right coolant is the one your engine specification lists. Brown or rusty coolant, or coolant with an oily film, is a sign to have the system checked.

### How do you check for a leaking head gasket?

We look for signs like coolant loss with no visible leak, white exhaust with a sweet smell, bubbles in the reservoir, or oil in the coolant. Then we test the coolant for combustion gases. The result goes on your estimate with an explanation before any repair decision.

## Related pages

- https://goodyearelitetireupland.com/services/belts-hoses-timing-belt/
- https://goodyearelitetireupland.com/services/air-conditioning-service/
- https://goodyearelitetireupland.com/services/filters-fluids/
- https://goodyearelitetireupland.com/about/resources/seasonal-vehicle-care/
- https://goodyearelitetireupland.com/contact/book-appointment/

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Call (909) 608-7699 or book at https://goodyearelitetireupland.com/contact/book-appointment/