Dorman 603-102 Front Engine Coolant Reservoir Compatible with Select Models

I replaced my radiator coolant reservoir in my 2003 Avalanche once the fluid level sensor stopped working. The main reason was due to the plastic reservoir turning yellow to the point you can’t see the fluid level. Yes I could have fixed the factory reservoir, but I really wanted to able to see the fluid level again. The fit of this reservoir was an exact fit and the original hose length from the radiator matched as well. No trouble with the installation, except I removed the air intake box to make the installation easier. It functions just like the original reservoir it replaced. Quality seems real good and I don’t expect any issues.

Works fantastic and super clear so you can see your coolant levels!!

the original coolant reservoir in my 2003 Avalanche had yellowed and discolored over the years making it near impossible to see how much coolant was actually in the tank. I put in this replacement tank when I installed a new water pump and it's so nice being able to see if the coolant level is holding steady or not. Well worth the purchase in my opinion.The only difference between this tank and my original one is the cap. The cap on the original tank specifically calls out to use Dexcool, the cap on the replacement tank does not. Aside from that I didn't see any difference at all. I choose to use the original cap and I'm keeping the one that came with the new tank as a replacement should the original fail later on down the road.

This really helps spruce up the engine bay. Fit my 2003 burb perfectly. Reused the original overflow hose instead of the included hard plastic aka wire loom overflow that this came with. Two bolts which were easy to get to for me but if you have stock airbox you may have to remove it to get to the other bolt.I drained about 1 gallon of antifreeze out to empty the overflow tank but you may get away with less. I just used the radiator petcock which is on the driver side lower part of radiator.Careful is using radiator drain as I had a slow drip afterwards and had to get the Dorman replacement 61136 petcock to fix the slow drip. So maybe just drain fluid by removing hose from surge tank.

Went in pretty smoothly in about 10-15 minutes. Mounting holes were slightly off but not difficult to install despite that.

Bolted in, no problems, nice replacement.

I never had to install one before, but it was pretty easy to install. My truck kept showing a low coolant in the dash even after I changed the water pump. I did not realize that the reservoir had a sensor in the bottom. Solved the problem. Great product and company. Quick delivery also. Thank you.

Easy swap for my 2001 Chevy half ton. Everything lined up as it should and quick work to replace.