Coolant leak after timing belt change?

[jcaroth]

Hi folks, I've got a '08 LGT with ~94k miles that I just replaced the timing belt on. I used the full Aisin kit with the bearings, belt, water pump, tensioner, etc. The new kit went on pretty smoothly and the car started up fine with no engine codes or strange noises (besides the usual ticking).

 

That said, after attempting to refill and burp the coolant, I noticed some steam/smoke floating up around the bottom edge of the timing cover, just beside the thermostat towards the passenger side. It had a slightly sweet smell, so I initially dismissed it as steam from spilled coolant on the exhaust piping.

 

I left the car overnight, then came back after work today and tried to burp it again. Smoke was still rising from that area at first, but strangely, when I removed the driver's side timing cover (to check the belt) the smoke was no longer visible. I reinstalled the cover, then let the car idle to get up to temp so I could check that the fans would turn on. The smoke reappeared.

 

By the time the temp gauge had risen halfway I noticed a coolant drip under the car. I traced the coolant up and it appeared to originate from the top of the radiator on the driver's side. At that point I noticed significantly more steam rising from the top of the radiator near the cap and surrounding area. The car had been idling for ~5 minutes by this point.

 

Any ideas what could be causing this? The fans never turned on, so I suspect that I made a mistake with the waterpump or thermostat during my install. I also could have messed up some of the hose connections, but neither of the big radiator hoses were obviously loose or leaking. I poked around with a mirror and saw no leaks near the thermostat.

 

I'd appreciate any advice you might have!

[MilesA]

Here's a possibility. The stock radiator is kind of frail. By that I mean when it gets old it tends to develop fine splits or cracks. This is more likely to happen when the radiator hoses are changed or the radiator is removed/replaced. Sometimes, this results in a fine spray of coolant that you would not notice unless the engine was running and coolant hot. Weak areas are the plastic radiator hose connections and the area where the end tanks join the main body of the radiator.

 

Another possible source of leaks is the water pump gasket. But, it sounds like you ruled that out already.

[Max Capacity]

You may be leaned on the radiator and cracked the neck, common mistake, as said, it's plastic.

[jcaroth]

You may be leaned on the radiator and cracked the neck, common mistake, as said, it's plastic.

 

In that case, I have two questions:

1. Is there a good way to check the radiator for cracks/leaks besides just visual inspection? Could it also be a bad cap?

2. If the neck is cracked, do I need to replace the whole radiator? If yes, should I go aftermarket or track down an OEM replacement?

 

Thanks for the help!

[Max Capacity]

A good flash light and a visual inspection will reveal a crack around the top fitting.

 

Any auto parts store can get you a replacement radiator. You can't repair the crack.

 

FWIW, I replaced both cap's a few years back, just because of age.

[jcaroth]

Alright, so assuming my radiator is actually cracked and I get a replacement, that will solve one part of my problem.

 

Is it still safe to assume that the steam from the thermostat area is from some drips on the exhaust? How long would it usually take for that to burn/evaporate away?

[Max Capacity]

Before you buy anything, make sure you know where the leak is.

 

My Gates water pump was leaking 20,000 miles after the engine rebuild. It was dripping out of the weep hole onto the manifold.

 

Get a good flash light and look around.

[landark]

I had my timing belt/water pump replaced in December and I started smelling coolant in late May. It wasn't until early this month that I found the crack in the top tank. And I was only able to find it because it had started spraying coolant all over the front of the engine and there was dried coolant visible. I never saw smoke but I saw puddles. I took a flashlight and looked all around where the spray would be coming from and found a 1/2" crack that was invisible without direct light on it, even during the daytime.

 

It's possible that your radiator could be cracked in such a way that it is spraying toward the timing cover and the smoke you're seeing is residual burn off.

I never actually say mine spraying, even after getting it up to temperature.

 

But yes, before buying anything, find where it's coming from.

[jcaroth]

Alright, thanks everyone for the input. I had a really busy week at work, but I finally found some time to troubleshoot this issue. Turns out that you were all correct: the radiator had cracked at the top plastic tank near the radiator cap, and was slowly trickling coolant. I also confirmed that the smoke from the area of the thermostat was coming from the exhaust piping under the timing cover. Seems like all I need now is a new radiator!

 

I've placed an order for a new OEM-style radiator (Koyo A2778), new inlet and outlet hoses, and a new thermostat (I know, I shoulda swapped that when I had the water pump out, but it didn't occur to me then).

 

Any other things I should watch out for while doing the replacement? As best I can tell it will be pretty simple:

 

• Drain coolant
  
• Remove hoses and overflow tank, unplug fans etc
  
• Unplug the trans cooler lines, plug them up with a bolt to stop leaks
  
• Remove old radiator
  
• Install new radiator, hoses, overflow tank, trans lines, etc
  
• Fill and burp coolant
  

Am I missing anything?

[Max Capacity]

I use Peak Global coolant or Prestone from Walmart or a store like that. You can buy it full strength and mix it 50/50 with water.

[jcaroth]

I use Peak Global coolant or Prestone from Walmart or a store like that. You can buy it full strength and mix it 50/50 with water.

 

I am finding mixed opinions on this. It seems a lot of people suggest only using Subaru coolant/conditioner. Is that not necessary?

[08SpecB_DE]

Depends how anal you are. The conditioner is more important than the coolant brand.

[jcaroth]

Good to know. Thanks for the tip

[MilesA]

If you recently changed your coolant, you can recover it when you drain the system and just reuse the coolant. You may need to top it up a bit. If you don't have the Subaru coolant, Peak Global or Prestone is fine, too. Just avoid the Dexcool stuff and don't mix incompatible coolants. Use distilled water to dilute the 50/50 mix.

[Max Capacity]

I am finding mixed opinions on this. It seems a lot of people suggest only using Subaru coolant/conditioner. Is that not necessary?

 

All I have every used in all my cars is Prestone or peak. My wagon I bought new in June 04. Never had a coolant related issue.

 

 

BTW, I top off the tank a couple times a years, takes may be a cup or less in the overflow tank.

[landark]

The replacement isn't too bad. Mostly time consuming and messy. And time consuming because of disassembly - which isn't hard just tedious. If you didn't already replace your hoses, I'd suggest doing that while you're at it. It took me about 4 hours from when I pulled out my sockets until I wiped them down and put them away.

 

I ended up using Subaru long life coolant - no conditioner. It's not that much more expensive than what I found the Zerex Asian coolant I used for my 60k mile service to be. But if you keep up with your services, you shouldn't have any trouble using whatever you prefer.