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2007 Trailblazer LT
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Discussion Starter #1 (Edited)
I have an oil leak on the lower driver side of the engine. The front diff area and the oil pan are all soaked as well as the frame behind that. Mid and upper engine is totally dry. I know most might say it is just a front diff problem but my engine oil is going down regularly. Lost about half quart in the past two weeks and another half in the two weeks previous. I just can't find where it's actually leaking from despite being under the truck every day. Where is the most likely leak site given what I've posted?

Thanks
 

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2004 chevy trailblazer_ls_ext
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175 Posts
My only though is to have the bottom steam cleaned and then watch very closely for the leak. Sorry I can't be more help.
 

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2004 chevy trailblazer_lt
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Put a piece of cardboard on the ground, and park your TrailBlazer over it and see what is directly over the drips. It could be a leaking oil pan gasket, a leaking output seal on the differential, a power steering system leak etc.

Have you checked your fluid levels lately to see which ones are normal and which ones are low?
 

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2007 Trailblazer LT
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Discussion Starter #5
Put a piece of cardboard on the ground, and park your TrailBlazer over it and see what is directly over the drips. It could be a leaking oil pan gasket, a leaking output seal on the differential, a power steering system leak etc.

Have you checked your fluid levels lately to see which ones are normal and which ones are low?
Engine oil is going down by about half a liter every few weeks which is about every 1000KM. All other fluids are normal. Cardboard thing not really helping cause oil has spread all over the frame and you can find a drip just about anywhere on the driver side once the truck is parked. Not really seeing puddles.

Given that I know it is engine oil and it's on the driver side, I'm just wondering what are the most obvious points for a leak? What kind of job is a basepan repair? Pretty sure nothing is rusted out, but the gasket might be a possibility...
 

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2004 chevy trailblazer_lt
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I can't answer how difficult it would be to drop the oil pan.
 

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2007 Trailblazer LT
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Discussion Starter #8
Got under the truck again today and followed the drops carefully. Looks like it's coming from the driverside of the oil pan. The mess all over the frame etc. must be getting thrown back while driving. Just next to the pan on the driverside is the differential, right?... It looks like two parts that bolt together... it's between that and the oil pan that the droplets appear most with some running down onto the pan itself and even onto the drain plug. But like I said, it is engine oil, so I suspect the pan gasket. I've spent a small fortune on this truck in the last year, so I can't fix it now. Is there any stop leak product worth trying or is it risky/pointless to even bother? Should I expect this to just get worse until it's fixed?
 

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2004 chevy trailblazer_lt
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I can't recommend any stop-leak products, but I do know that High Mileage oils (like Havoline, Valvoline, Quaker State, etc.,) do contain extra seal conditioner additives that often slow down, and in some cases even stop, small oil leaks or oil weepings. This is the route I would go until you can find the time and $$$ to fix the problem properly.
 

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I have an oil leak on the lower driver side of the engine. The front diff area and the oil pan are all soaked as well as the frame behind that. Mid and upper engine is totally dry. I know most might say it is just a front diff problem but my engine oil is going down regularly. Lost about half quart in the past two weeks and another half in the two weeks previous. I just can't find where it's actually leaking from despite being under the truck every day. Where is the most likely leak site given what I've posted?

Thanks
This sounds just like the leak I had on mine. It was all under the engine running back under the truck. Mine was a leaking front main seal. Check under/behind your damper if you can. May have to clean everything and then check again. I bought a new seal and a new damper since I had to pull the damper off. Replaced the seal, put it back together, solved my leak problem. Hope this helps find your leak.
 

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2006 Chevrolet Trailblazer LS
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28 Posts
Go to parts store and get some engine oil dye.
Follow the instructions.
Good luck!
 

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I have an oil leak on the lower driver side of the engine. The front diff area and the oil pan are all soaked as well as the frame behind that. Mid and upper engine is totally dry. I know most might say it is just a front diff problem but my engine oil is going down regularly. Lost about half quart in the past two weeks and another half in the two weeks previous. I just can't find where it's actually leaking from despite being under the truck every day. Where is the most likely leak site given what I've posted?

Thanks
Try looking at the oil sending unit cost about 20 bucks brand new from auto zone literally a plug and play when it goes out it will spray oil out of it replacing this really helped my oil leak problem it doesn't require any tools to change just have to know what and where to look for it
 

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2003 gmc envoy_sle
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I know this may sound too obvious, but sometimes the obvious gets overlooked. Have you checked to see if the oil pan bolts are as tight as recommended. It wouldn't be the first time it would happen to someone, on any car.
 

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2008 chevy trailblazer_lt
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Older 4.2's apparently had the oil pressure sender on that driver's side. Newer ones like yours should be at the back passenger side head. I'd think that valve cover, timing cover and front main or might be the only places that it should leak on that side, besides the oil pan. The cam phaser and sensor for it should be on the passenger side. Good luck. Long ago when I had a front main leak, (small block Chevy V-8), I tried a couple of tablespoons of brake fluid in the oil, per suggestion from someone in the transmission rebuilding business. It sure slowed it down, but I still had the motor pulled for new front main and oil pan gasket back then. When I had a bad power steering leak, the Lucas stop leak for it was the one that slowed that way down for me, while Prestone Power Steering Fluid with Stop Leak didn't seem to help much.

Rob in AZ
 

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2004 gmc envoy_slt_xuv
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I have an oil leak on the lower driver side of the engine. The front diff area and the oil pan are all soaked as well as the frame behind that. Mid and upper engine is totally dry. I know most might say it is just a front diff problem but my engine oil is going down regularly. Lost about half quart in the past two weeks and another half in the two weeks previous. I just can't find where it's actually leaking from despite being under the truck every day. Where is the most likely leak site given what I've posted?

Thanks
I would be looking at the axle that goes through the oil pan. seal leak.
 

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2007 Trailblazer LT
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Discussion Starter #16
Sorry for not posting back; wasn't getting reply notifications...Anyway, still battling the leak, seems impossible to track the exact source. But it's way way down on the bottom of the engine, not even high enough to get on the belts or pulleys up front... Someone above mentioned the front main seal... what kind of cost and labour is that?

I have to take the truck in for new upper control arms in a couple weeks so I'll know for sure then where the leak is from when I see it on a ramp, but I'm kinda dreading it. I don't mind fixing **** but the labour fees are the worst. Hoping it's nothing catastrophic!
 

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Sorry for not posting back; wasn't getting reply notifications...Anyway, still battling the leak, seems impossible to track the exact source. But it's way way down on the bottom of the engine, not even high enough to get on the belts or pulleys up front... Someone above mentioned the front main seal... what kind of cost and labour is that?

I have to take the truck in for new upper control arms in a couple weeks so I'll know for sure then where the leak is from when I see it on a ramp, but I'm kinda dreading it. I don't mind fixing **** but the labour fees are the worst. Hoping it's nothing catastrophic!
I just pulled it up online to see where it refers to it being its close to the front of the crankshaft but to get to it will require tearing a good chunk of the front of the motor apart if done properly you may be able to short cut it by going under the truck but either way your probably gonna be looking at about 400 to 1000 depending on your shop of choice of course but its allot of labor going into it to replace it i don't think the part will cost you no more than 20 bucks i could be wrong on part price but labor I should be at least in the ball park
 

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2007 Trailblazer LT
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Discussion Starter #18
Thanks for posting. What's more likely ... front main seal or leaking oil pan? - that is what I have been suspecting given the location and all the stuff I've read.

Which seems more probable? Which is more expensive?

And finally, what exactly is the main seal called if I wanted to look it up for pricing? I'm in Canada so parts are very expensive. Any part numbers?
 

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I have an oil leak on the lower driver side of the engine. The front diff area and the oil pan are all soaked as well as the frame behind that. Mid and upper engine is totally dry. I know most might say it is just a front diff problem but my engine oil is going down regularly. Lost about half quart in the past two weeks and another half in the two weeks previous. I just can't find where it's actually leaking from despite being under the truck every day. Where is the most likely leak site given what I've posted?

Thanks
Thanks for posting. What's more likely ... front main seal or leaking oil pan? - that is what I have been suspecting given the location and all the stuff I've read.

Which seems more probable? Which is more expensive?

And finally, what exactly is the main seal called if I wanted to look it up for pricing? I'm in Canada so parts are very expensive. Any part numbers?
It could really be either one in that location both the oil pan and the seal are connected in the front of the motor so if its the oil pan should be a little cheaper as you can go under the motor if its the seal though its gonna cost more to fix because it requires more of a tear down I do not have any part numbers however I will try to see if I can find any for you to give you a reference I may be able to find you one cheaper on Amazon i have saved tons of money going though them fixing my trailblazer
 

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It could really be either one in that location both the oil pan and the seal are connected in the front of the motor so if its the oil pan should be a little cheaper as you can go under the motor if its the seal though its gonna cost more to fix because it requires more of a tear down I do not have any part numbers however I will try to see if I can find any for you to give you a reference I may be able to find you one cheaper on Amazon i have saved tons of money going though them fixing my trailblazer
More probable cause I would say the oil pan
 
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