Turbo owners: Read before turning the coolant tank sideways!
Posted: Sat Mar 05, 2005 11:31 pm
In some other threads I've suggested to people installing intercoolers that a neat way to avoid having the intercooler interfere with the coolant filler tank is to remount the tank sideways, using one of the original two mounting holes but with the other hole of the tank.
I did that many months ago, and it seemed good. But occasionally I'd notice some dried coolant around the radiator cap neck. I had removed and installed that cap many, many times, so I figured the rubber gasket built into the cap just wasn't sealing anymore. I'd just wipe it up and refill the overflow tank periodically, and I planned to get a new rad cap.
So a couple days ago I finally put a new cap on, proud of myself for promptly fixing the problem five months after noticing it.
But the problem was still there.
That was worrisome... I started wondering if the tiny bit of overheating that happened each time I broke the tank could have caused damage to a head gasket. So then I dropped by a local shop and asked them to test for exhaust gas in my coolant. It was clean.
I finally figured out what was causing the radiator cap to leak. The tank in its new position was slightly higher than its original position. When the engine rocked on its mounts, the cap would actually bang on the hood hard enough to temporarily unseat the gasket and spray some coolant out.
So... Don't just remount it sideways using the stock mounting point. Until I figure something else out, I've just eliminated the filler tank and am idling longer when I park.
Edit: Changed title to reflect the fact that Matt posted useful info below
I did that many months ago, and it seemed good. But occasionally I'd notice some dried coolant around the radiator cap neck. I had removed and installed that cap many, many times, so I figured the rubber gasket built into the cap just wasn't sealing anymore. I'd just wipe it up and refill the overflow tank periodically, and I planned to get a new rad cap.
So a couple days ago I finally put a new cap on, proud of myself for promptly fixing the problem five months after noticing it.
But the problem was still there.
That was worrisome... I started wondering if the tiny bit of overheating that happened each time I broke the tank could have caused damage to a head gasket. So then I dropped by a local shop and asked them to test for exhaust gas in my coolant. It was clean.
I finally figured out what was causing the radiator cap to leak. The tank in its new position was slightly higher than its original position. When the engine rocked on its mounts, the cap would actually bang on the hood hard enough to temporarily unseat the gasket and spray some coolant out.
So... Don't just remount it sideways using the stock mounting point. Until I figure something else out, I've just eliminated the filler tank and am idling longer when I park.
Edit: Changed title to reflect the fact that Matt posted useful info below
