# Radiator Pressure Testing in Upland > Not sure the radiator is the leak? Route 66 Auto Repair in Upland pressure tests the radiator itself to pin down tank, seam or core leaks before quoting. Source: https://route66autorepairshop.com/cooling-heating-ac-services/radiator-pressure-testing Updated: 2026-09-17 Business: Route 66 Auto Repair, 1775 W Foothill Blvd, Upland, CA 91786, (909) 608-7699 Hours: Monday to Friday 8 AM–5 PM, Saturday 8 AM–2 PM, Sunday closed **TLDR:** This test targets the **radiator only**: tanks, crimp seams and core. It keeps you from buying a radiator when the **real leak** is a hose or cap. A radiator pressure test answers one question: is the radiator itself leaking, or is the coolant going somewhere else? Route 66 Auto Repair in Upland pumps the cold system to its rated pressure and inspects the radiator tanks, seams, necks and core with a light and a mirror. You get a clear yes or no, with a photo, before anyone quotes a new radiator. ## When should the radiator be pressure tested? - Someone quoted a radiator but never showed you the leak - Coolant drips at the front of the car but the source is unclear - The radiator took a hit from road debris on the I-10 - You see crust at a tank seam and want to know if it is active - Before buying a used car with a replaced front bumper ## What does the pressure gauge tell us? We pump the system to the pressure printed on your cap and watch the needle. A steady needle with a dry radiator clears the radiator. A falling needle with coolant beading at a tank seam, a neck or between the core tubes points straight at the radiator. A falling needle with a dry radiator sends us to hoses, the pump or inside the engine. Some radiator leaks only open when hot. If the cold test passes, we can warm the engine and look again. That wider search is the [cooling system pressure test](https://route66autorepairshop.com/cooling-heating-ac-services/cooling-system-pressure-test), which also checks the cap and for combustion gases. ## Our radiator pressure testing process 1. **Access:** We remove splash shields or covers so the whole radiator face and both tanks are visible. 2. **Pressurize:** The tester is attached at the filler neck and pumped to the rated pressure. 3. **Inspect:** Tanks, crimp seams, hose necks, drain valve and cooler line fittings are checked for seepage. 4. **Report:** You get the needle result, photos and a written next step. ## What's included in radiator pressure testing - Cold pressure test at the rated value - Inspection of tanks, seams, necks and drain valve - Transmission cooler line fitting check where equipped - Photos of any leak point - Written result with repair options ## Is it a need-now or need-later repair? **Need now:** - Pressure drops and coolant beads on the radiator - Wet core after debris damage **Need later:** - Holds pressure with old dried residue - Minor fin damage with no leak ## How pricing and timing work The test is billed as diagnostic time. The fee is stated at the counter before testing and applies to approved related repair, such as [radiator repair](https://route66autorepairshop.com/cooling-heating-ac-services/radiator-repair). Most tests are done while you wait if the board allows. Bent fins found during the test are covered on [radiator fin repair](https://route66autorepairshop.com/cooling-heating-ac-services/radiator-fin-repair) and are usually a later item. ## Aftercare If the radiator passed, keep an eye on the level and where any drip lands. Note whether it happens after short trips or long drives; that detail helps us find a leak that only opens when hot. The test result stays on your repair order for next time. ## Frequently asked questions ### Can a radiator leak only when the engine is hot? Yes. Plastic and aluminum expand at different rates, so a tank seam can seal cold and weep hot. We can repeat the look at operating temperature. ### Does the test damage anything? No. We use the pressure your cooling system is designed for, never more. That is the same pressure it sees on every drive. ### Can I do this test with a rental tester? You can, and it is a good first step. Knowing where to look on your model, and what a slow drop means, is where a technician helps. --- Call (909) 608-7699 or visit https://route66autorepairshop.com/contact for a written estimate.