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spark plug access, 2003 toyota highlander 3.0

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Want to change the spark plugs on my 2003 Toyota Highlander 3.0, 43,000 miles.  Front plugs are easy to access, but rear plugs seem like a bear to get at (can't even see them.  Alldata says 2.8 hrs. for plug change, but they give no specifics or step by step.  Based on 2.8 hr labor time, I can only assume that the intake plenum needs to come off.  Can anyone verify this or are there any shortcuts.  Truck runs fine, but I think after 5 years they should be changed.  Thanks in advance for any advice.  My best to all for a happy and safe holiday.
Frank F.

Jim Fairbanks:
Frank...I have never done them on a Highlander yet, maybe one of the others on here have, but I did a search and found some info that might help you.....Jim.......................
 I just did a 2003 Highlander 6cyl ---my colleague below is correct the rear plugs are behind the intake manifold, not the exhaust manifold -- you do not have to remove the intake manifold to change the rear plugs, just small hands and patience. It helped me to work from the right of the intake manifold to the left. Remove the two screws on the choke assembly on the left side of the intake manifold. Just below the choke assembly is a short fat rubber that should be pulled off at both ends. On the right side of the intake manifold remove the cruise control cable and the assembly ( one bolt). There may be one or two vacuum lines running through the area, they should be disconnected and moved out of the way. Prop the hood of the car on the far right hand side because the normal hood bar will get in your way. Even if you are tall you will need something to boost your height at the front of the vehicle so that you can reach the back of the engine.

See the tool suggestions and hints in the other post -- they are very good. I recommend removing all of the spark plugs and the seals working right to left in order to provide room to work. Re-assemble left to right. The most difficult part is removing the electrical connection from the coil that sits right on top of each firing point. Because you are not able to see removing the connectors is by feel -- I found that using a thin washer to pry up the plastic clip helped a great deal. Experiment on the front electric connectors to get a process down - they are easy to reach.

Allow 4 hours - if you do it in less than 3 in your driveway, then you are a master mechanic.

I tried to add my suggestons but I ended up being listed on an entire new post. After reading these suggestions, which are helpfull, please see the other question and answer about spark plugs on a 2002 toyota highlander (I think the word Toyota must be used in the search.... I agree with the answer listed on this post, but I also listed some other suggestions that worked well for me.

changing plugs in toyota highlander
in the transversely mounted v-6 1 mz engine of the Toyota highlander simply remove engine cover to get at front three spark plugs. you will need A 5/8 spark plug socket with rubber gasket inside (in order to grip the plug )as you pull it out. Also a 6 inch extension with socket wrench will be needed to reach the recessed plugs. Now comes the fun part! I have been told by my local toyota dealer mechanic that the rear 3 spark plugs( the ones closest to the firewall and underneath the exhaust manifold) can be removed 2 ways. One is to raise the suv on a lift and they can be reached by sticking your arm between the engine and firewall from underneath the car. the other way and the way the highlander maintenance manual shows is to remove exhaust manifold at right side of engine. some fairly large bolts need to be loosened and it needs to be put back on correctly or you will have an exhaust leak. There is a third way however. By reaching your hand around and under the exhaust manifold you can get your hand on the insulators that hold the plugs in their respective cylinders.( the smaller your hands are the better). there is a small nut holding each insulator in place. Take your socket wrench and 4 or 5mm socket and slide it under exhaust manifold and begin to loosen the long bolt holding each insulator in place. Its very slow going ( I could only get a 1/4 to 1/2 turn on the insulator bolt). Once the bolt is loose use your fingers to loosen it the rest of the way. Again its very tight quarters and I did a lot of the work by feel not sight. Once the insulators are removed take your extension and spark plug socket and feed it down the spark plug cyclinder hole and loosen the plug. Once loose, use your fingers again to loosen each plug the rest of the way. there is no room to use the socket wrench so most of the loosening and tightening needs to be done by hand. It took me 4-5 hours to complete the job. But the alternative is to spend 180.00 bucks and let a toyota dealer do it.

Thanks for the excellent reply.  The info was exactly what I was looking for.  Since the weather is not the best for working outside, I'm going to wait until it warms up a bit.  As I mentioned in my previous post, this is strictly a maintenance procedure as the vehicle runs perfectly.  I sure do miss my '55 Chevy with a 1 piece tilt fiberglass nose.  Used to tilt the nose, sit on the front tire and change the plugs (among other things) in the blink of an eye.  Thanks again for the info.  My best to all for a safe and happy holiday.

Jim Fairbanks:
You are welcome...Glad we could help..Jim

Since your highlander has only 43,000 miles you may be changing the plugs prematurely. Please check a good service manual to find out for sure when the plugs should be replaced.


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