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Discussion Starter · #1 · (Edited)
Hello,

I am having issues with the coolant system in my 03 Toyota Highlander. It's a 2 wheel drive 4 cylinder.

The immediate issue is, there is fluid coming out of the overflow reservoir and fluctuating temperature. It randomly climes a little over the half way mark then cools back down.

After extended driving, I shut the vehicle off and look under the hood and occasionally, I notice coolant that has sprayed out of the coolant overflow reservoir and if it hasn't released pressure, I notice bubbles coming out of the overflow hose inside the reservoir.

I have replaced the radiator, the thermostat, the radiator cap and flushed the system with new coolant and it continues to do the same thing.

On a strange note, the overflow issue began when I changed the radiator cap. A mechanic and I noticed someone had placed and extra piece of rubber inside the cap almost to say that when we purchased it from the dealer, this issue was already there, and the quick fix was to block and overflow.

My next troubleshooting adventure is to replace the water pump but I'm reluctant to do so because my thinking is. If the water pump was failing, wouldn't there be water seeping out of the weep hole? Wouldn't it just fail all together after a period of time?

I'm desperate at this point because I'm beginning to think there's a possibility of either a cracked head, or a blemished head that's allowing pressure to escape the cylinders (ever so slightly) and enter into the coolant system.

What could possible be causing this and thanks you in advance for any suggestions.

EDIT* Also, there are small black deposits within the reservoir and and oder of burned oil.
 

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AvConsult
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Mobster, your articulate description of the problem points to what you fear; a head gasket failure or internal block crack that is over-pressurizing the cooling system.

I'm guessing the former, since failed head bolts are a know problem in Toy HL 4 cyl. If you are an accomplished DIY, then pull the valve cover and check the head bolts, or take it to a garage. If it's loose head bolts, then the block threads failed. There are several detailed posts in this forum towards re-working the block.

Bummer. :disappoin
 
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Discussion Starter · #3 ·
Ahhgh! You know when we purchased this thing with 40,000 miles, it blew a little blue smoke in the morning. I suspected then, the vehicle had priorly overheated. The extra piece of rubber I found (180,000 miles later) now confirmed it. My guess is, someone overheated the vehicle, traded it in, or took it to a mechanic that temporarily masked the issue by blocking the overflow. At the tail end of the vehicles life, as we all know, is when these things start to surface.

I talked with a mechanic friend today that mentioned it's possible even when the head was first cast, there may have been a defect or porous spot in the head that allowed pressure to build up gradually which could have caused the vehicle to overheat in the first place early on in the vehicles life.

Long story short, with a engine with 200,000 miles on it, I'm not sure I want to put a single penny in it.

Thanks for your reply.
 

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AvConsult
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The blue smoke ring is probably unrelated to radiator issue. Toyota's have had problems with hardened valve stem seals, which allows oil to seep past and onto the back of the valve and into the cylinder. They are also very fussy about PCV condition.

Some folks have had good results from running an engine flush product just before their oil change routine (like for two OCI's) and using the oil rated for "high mileage" cars. The additive package swells the seals a bit more.

I'd venture the block/radiator thing has been there, since before you bought it, although to a lesser degree. Has anyone pressure tested the radiator while the car was running just to confirm the block leak?
 

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Discussion Starter · #5 ·
Weirdest thing. As a last ditch effort, I replaced the water pump. At first inspection, there didn't seem to be anything wrong with it. There were no visible leakage, worn our bearings or broken shaft. I thought after removing it, I was just replacing it in vein. Needless to say, I carried on with replacing it since I had already purchased it and had the old one off.

Once I replaced it and had everything back together, I removed the overflow container, cleaned out the inside and re-installed it. I filled the coolant and went through the regular "burping" procedure.

I then let it run for nearly two hours to see it it would do the same thing. I then dove it on the highway at 80 plugs miles and hour for about 45 minutes. I pulled back in the garage and looked under the hood. No bubbling, no overflowing, no anything.

I let it sit overnight, restarted the vehicle and took it on another 80 mile an hour drive (about 40 minutes) pulled it back in the garage and nothing. The level in the overflow remained the same, no leakage, no bubbles again nothing.

Is it possible the water pump was (slipping) or defective when getting hot? I'm telling you, this is really weird.

I am going to get it compression tested just to be on the safe side. I'm also going to get an OEM radiator cap to see if there might be an issue with the cap. I used a different cap than the one I had when I was experiencing the issues.

Thanks again, Ill keep you posted.
 

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sounds like you got it, esp if the test drives replicated your situation when you were having the problem. I would just keep and eye on it for future problems, it could be as simple as your radiator is plugging up? But I think you got it.
 

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Discussion Starter · #7 ·
I spoke too soon. Now, almost a half a tank later, it's bubbling in the overflow again and I can smell coolant under the hood along with a little leakage or (blow by.)

Looks like it's time to move on to another vehicle. At 200,000 miles, I really don't see putting any money into it and it's a shame, it still looks good, runs good...
 

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If you are looking for an engine, this one has been for sale for a long time. The seller may be motivated.

http://richmond.craigslist.org/pts/3734471309.html
Great post, it might be worth for the O/P to get in touch with the seller and negotiate a deal, maybe $1500 installed? Sounds like the rest of the vehicle is in great shape, I wouldn't pay $5k-$6k at a dealer but below $2k would probably be worth it.

If it was me, I'd calculate kbb on it and if the repair is less than half the value of the vehicle I would do it, i.e. vehicle worth $2k it's not worth putting $1k into it. Vehicle worth $7k, it's worth putting $1k into it.
 
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