# Camshaft Seal Replacement in Upland > Camshaft seal replacement in Upland for oil seeping from the front or back of the head. We find the true leak source and write the estimate first. Source: https://route66autorepairshop.com/engine-services/engine-camshaft-seal-replacement 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:** A leaking **camshaft seal** can soak the **timing belt** in oil, so we confirm the source first and often pair the seal with belt work. A camshaft seal is the round lip seal where the camshaft pokes out of the cylinder head. When it hardens, oil creeps out and lands on the belt, the exhaust or your driveway. Route 66 Auto Repair in Upland replaces cam seals after we clean the area, confirm the seal is the source, and check whether the oil has already soaked the [timing belt](https://route66autorepairshop.com/engine-services/timing-belt-replacement). ASE-certified technicians do the work, and you approve a written estimate before any cover comes off. ## What points to a leaking camshaft seal? - Oil wetting the front of the engine near the top, behind the belt covers - A burning oil smell after a drive on the 210 as drips hit hot exhaust parts - Oil spray flung in a line across the inside of a timing belt cover - Drops under the passenger side front of a transverse engine after parking ## How do we tell a cam seal from other leaks? Oil runs downhill and gets blown backward by the fan, so the wet spot is often inches from the real leak. We degrease the front of the engine, add a trace dye when needed, and run it. A UV light then shows the first place oil appears. That separates a cam seal from a [valve cover gasket](https://route66autorepairshop.com/engine-services/valve-cover-gasket-repair), a crank seal or a cracked cover. General seepage checks are covered on our [engine oil leak repair](https://route66autorepairshop.com/oil-change-services/engine-oil-leak-repair) page. ## Our camshaft seal replacement process 1. **Confirm the leak:** Clean, dye and run the engine so the seal is proven to be the source. 2. **Lock the timing:** On belt and chain engines we mark and hold cam position before loosening the sprocket. 3. **Remove and fit:** The old seal comes out without scoring the bore, and the new seal goes in square to the correct depth. 4. **Reassemble and verify:** Sprocket bolts go back to spec, the engine is rotated by hand twice, then started and road-tested. ## What's included in a camshaft seal job - Leak source confirmation with cleaning and dye as needed - Timing marks checked and recorded before and after - New cam seal installed to the listed depth - Inspection of the belt, tensioner and idler for oil damage - Road test and a recheck for fresh seepage ## Is a cam seal leak need-now or need-later? **Need now:** - Oil reaching a rubber timing belt, which can shorten its life - Oil dripping onto the exhaust manifold and smoking **Need later:** - A damp film with no drips and a dry belt - Seepage you can monitor at each oil change ## How pricing and timing work A cam seal behind a timing belt means the belt comes off, so the estimate usually suggests doing the belt at the same time rather than paying for that labor twice. Your written estimate lists each item before we begin, and AAA members save 10% on parts and labor, up to $75, with the card at time of service. Many cam seal jobs finish in a day when the board allows. ## Aftercare Look at the front of the engine after a week of normal driving. Fresh oil means a return visit, and comebacks go to the front of the line. ## Frequently asked questions ### Should I replace the timing belt at the same time? If the seal sits behind the belt and the belt is oily or near its service interval, pairing them usually saves labor. If the belt is new and dry, it can often go back on. We show you the belt and let you decide. ### Is a cam seal leak dangerous? A slow seep is not an emergency. Oil dripping on a hot exhaust can smoke, and oil on a timing belt can weaken it, so those cases should be booked soon. ### Why does my engine have oil at the back of the head? Many engines have a rear cam seal or a cap plug at the back of the head. It fails the same way as the front seal, just out of sight near the firewall. The dye test tells us which end is leaking. --- Call (909) 608-7699 or visit https://route66autorepairshop.com/contact for a written estimate.