# Coolant System Air Purge in Upland: Clearing Trapped Air > No heat and a gurgle after coolant work? Route 66 Auto Repair in Upland purges trapped air and checks whether air keeps coming back from a deeper problem. Source: https://route66autorepairshop.com/cooling-heating-ac-services/coolant-system-air-purge 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:** One **air pocket** after service is easy to clear. Air that **keeps coming back** is a symptom, and we test for the cause before calling it done. Trapped air in a cooling system causes a gurgle behind the dash, heat that comes and goes, and temperature spikes. Route 66 Auto Repair in Upland purges the air using the method your engine calls for, often a vacuum fill, and then asks the important question: was this one pocket from a recent service, or is air entering the system again and again? ## What are the signs of air in the cooling system? - Gurgling or trickling sound behind the dashboard - Heater that blows hot, then cold, then hot again - Temperature gauge spikes that drop back quickly - Reservoir level that drops in the first days after a service - Bubbles in the reservoir with the engine running ## Is it a one-time pocket or recurring air? Air gets in any time the system is opened: a hose change, a water pump, a DIY coolant swap. Many modern engines have the radiator mounted lower than the heater core or the cylinder head, so air settles at the high points and will not leave on its own. That kind of pocket is cleared once and stays gone. Air that returns after a proper purge is different. It can come from a hose joint pulling in air as the engine cools, a cap that will not hold, or combustion gas pushing into the coolant. That is why we recheck after a heat cycle and, if bubbles return, run a [coolant system contamination test](https://route66autorepairshop.com/cooling-heating-ac-services/coolant-system-contamination-test) for exhaust gases. ## Our air purge process 1. **Check the history:** We ask what work was done recently and check the level, cap and hoses for obvious air leaks. 2. **Vacuum fill or bleed:** A vacuum fill tool pulls the air out before coolant goes in, or the engine is bled at its bleed screws in the correct order. 3. **Heat cycle:** The engine runs to full temperature with the heater on high, and we watch for bubbles and steady heat. 4. **Cool-down recheck:** After it cools, the level is checked again, and any drop means we look for a source. ## What's included in a coolant air purge - Level, cap and hose check for air entry points - Vacuum fill or bleed-screw purge per engine design - Coolant of the type your engine specifies to correct the level - Heat cycle with heater output check - Cold recheck and notes on any recurring air ## Should trapped air be cleared right away? **Need now:** - Temperature spikes toward hot - No heat at all with a gurgle - Bubbles that keep coming after a purge **Need later:** - A faint gurgle at startup that fades - A small level drop in the first days after service ## How pricing and timing work A purge takes time because the engine has to heat up and cool down. Some engines need a specific sequence and more waiting. If we find an air leak or a failed cap, it goes on the written estimate before any repair. If testing shows gas in the coolant, we stop and explain. The fee is stated at the counter before we start, and most purges are done in one visit when the board allows. ## After the purge Check the reservoir cold for about a week. Steady heat and a quiet dash are good signs. If the gurgle returns, bring it back and we will recheck at the front of the line. The step-by-step bleeding procedure itself is covered on [coolant system bleeding](https://route66autorepairshop.com/cooling-heating-ac-services/coolant-system-bleeding). ## Frequently asked questions ### Can I burp the air out myself? On some older vehicles, running the engine with the cap off can help. On many newer engines, the high points trap air and a vacuum fill or specific bleed order is needed. ### Why did air appear after a shop changed my coolant? Some engines are hard to bleed completely in one pass. A small pocket can move to a high point during the first drives. A recheck usually clears it. ### Can trapped air damage the engine? A large pocket at the sensor or cylinder head can cause local overheating. That is why a spiking gauge should be checked promptly. --- Call (909) 608-7699 or visit https://route66autorepairshop.com/contact for a written estimate.