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Yesterday I noticed a couple small spots on my driveway under the front passenger side of my 06 trailblazer. About the size of a baseball. It was still wet and at first glance/touch, it seemed like oil. I didn't notice a red tinge to it, but then again it was sitting on asphalt.

After looking under the car, it seems that there is oil all over the bottom of the radiator. My oil level and transmission fluid levels look fine. The oil seems to be in the vicinity of the transmission fluid line where it enters the rad on the passenger side. I have attached pics.

I recently (a month or so ago) replaced my water pump and fan clutch and when removing the fan shroud, I did notice the transmission fluid lines are pretty rusty. I'm wondering if the process of pooping those lines out of and into the fan shroud caused a leak, possibly at the quick connect where it enters the rad? This seems the most logical to me.

The oil/fluid seems to be finding it's way to the corner of the underside of the passenger side bumper and dripping from there as well.

I ran the truck for a bit today and didn't see anything leaking while running, so I'm assuming it's a slow leak (although it does accumulate while sitting in the driveway over the period of a couple hours).

I put a white container under there to catch more leakage and I'm hoping it will verify that it's transmission fluid (red-ish) and not oil. No oil in my coolant that I can see (opening cap and looking inside). I flushed/replaced coolant when I did the water pump.

At this point I'm hoping to get as much life out of this truck as makes sense. I don't really want to replace the transmission fluid lines if I don't have to (sounds expensive for the dealer/shop to do it, and a huge pain in the ass to do it myself). I'm wondering/hoping if it's perhaps just a bad oring in the fitting at the rad?

Any thoughts? Thanks.

55475


55476


Note: above pic is looking down the front of the rad. You can see some oil accumulated in the bottom here. Not sure how a leak at the quick connect fitting on the back would result in oil here??
 

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Until you know what color the fluid is, all we can do is speculate. You could be seeing a weeping leak from the transmission cooler oil line fitting - either from the o-ring on the oil line or from where the fitting screws into the radiator. It could be coolant weeping out from small seam leak where the side tank mounts to the radiator, weeping from the upper radiator hose or filler neck (small crack or bad radiator cap). It could even be AC oil from a tiny hole in the condenser. It could even be a leak from the rusted transmission lines.

Replacing the transmission oil cooler lines can be a real pain in the behind. I replaced mine a few years back but because I could not reach up the side of the transmission to disconnect the lines from the transmission, I purchased a couple of brass compression fittings, cut the lines near the transmission and spliced the new lines into the existing lines where I cut them. Fortunately for me, the lines near the transmission where I cut them were not rusty.

Please report back with the color of the fluid so we can be of more assistance to you.

Good Luck!
 

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Discussion Starter #3
Thanks pslcolla,

I captured some of the fluid in a container and compared the color to that of both my transmission fluid and oil (from dip-sticks). I was expecting more of a red tinge to my transmission fluid, probably in need of a change.

55480


It's subtle and perhaps hard to tell from the picture, but based on this I am pretty sure it's transmission fluid that is leaking at or near where it enters the rad. I found this older thread that seems eerily similar to what I'm seeing and thinking:


If my problem is the same, it appears I should be able to only replace the smaller section of line that attaches to the rad on the passenger side, between the two quick connect fittings (which looks cheap and simple). Still somewhat concerned over the amount of rust on the rest of my transmission lines, but no leaks other than this section at the moment.
 

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I'm not getting a good view of you leak.

I know you've checked you transmission and engine oil levels - but how about your power steering reservoir?

There is a steering oil cooler just ahead of the lower part of the radiator and a leak at it might drift back to the radiator, confusing your observations.

Then ........ there's always the TASTE TEST to positively, 100%, identify the mystery fluid.

Coolant = sharp sweet initial taste, lingering to a bitter aftertaste that's hard to eliminate.
ATF = musky, somewhat metallic with overtones of burnt shellac.
Power steering fluid = very "chemical" taste with a rubbery scent and back of the throat oiliness.
Engine oil = varies by brand with Castrol as my favorite because it's the same frying oil they use at McDonald's.

I'm not including brake fluid, differential lube or windshield fluid --- each are a taste treat unto themselves for a true automotive gustatory expert.
 

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I have to agree with Ravalli, it's really tough to tell what color the fluid is. I have never seen amber colored automatic transmission fluid myself, but when I changed the power steering lines and cooler on my 04 TrailBlazer, the power steering fluid I put in to the system was sort of an amber/straw color.

If your fluid levels are not dropping significantly, then you'll need to add some uV dye to the various fluids - engine coolant, engine oil, ATF, power steering, one at a time and drive around for a week and then using a uV light, see if the spills on the driveway or wet areas glow under the light. If nothing, then add uV dye to the next fluid and drive around for another week and repeat the process.

DO NOT add uV dye to all the fluids at one time otherwise you'll never determine which fluid is leaking out.
 

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Discussion Starter #6 (Edited)
Thanks guys, especially for the hint about the power steering cooler in front of the rad (hadn't considered that). I spent some more time looking at it and my fluids. I had checked the power steering level and it looked ok, but when I was checking the different liquids I must have accidentally mixed up the transmission and power steering fluid. The color and consistency is actually much closer to the power steering fluid than the transmission fluid (which does indeed have a more red tint to it). Some crappy initial diagnosis I did there...

Considering the color and consistency, fluid in front of the rad, leaking down the bumper cover, seems highly likely it could be coming from the PS cooler or that area. Fluid level is perhaps ever so slightly low, just below the cold line (it is a pretty slow leak though).

New cooler is about $200 (CAD) shipped. If that's what it turns out to be, is that a fairly simple repair? If it's the lines themselves or something else, I guess that's another matter.

Edit: View of the cooler looking through front bumper cover on passenger side. Sure looks like the prob (oil/fluid is dispersing out from there). Why didn't I look here first? :oops:

55490
 

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Replacing the power steering fluid cooler is not a difficult job. One has to move some plastic body panel out of the way, undo the 2 hose clamps and a couple of fasteners, and then it comes off.

Be sure and check the price for a new one on rockauto.com. My understanding based on postings on another automotive forum is that even with the conversion between US & Canadian dollars, and shipping, rockauto.com can save you some $$$. For what it's worth, when I replaced my power steering fluid cooler, I used a Dorman cooler rather than an ACDelco cooler and saved about 1/3rd. It fit perfectly and was well made.
 

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Thanks. I checked rockauto and it was 3 dollars cheaper (shipped) for the Dorman than Amazon (which had much faster shipping). So I went with Amazon. Part will be here tomorrow, already have the bumper apart and ready to install when it gets here. Will let you know how it goes.
 

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Don't discount the PS lines. I just had mine replaced on my '03 Envoy. Major pain.
 

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Discussion Starter #10
Got the new PS cooler today and installed it. Topped off PS fluid and took for a ride, so far everything looks good. My PS lines looked in decent shape, but as mentioned my transmission lines are pretty bad, very rusty (no leaks, but not pretty). If I had the energy I would try to replace them but I've just done too much work on this thing lately. That's perhaps my next project.
 
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