2002 Toyota 4Runner Engine Help

[jwkiss0]

My wife was waiting in the school when the check engine light came on and the temperature guage spiked. She turned it off immediately. I checked it out and the radiator lost some fluid. It lost the amount in the overflow tank. I refilled the overflow. After it sat we restarted it and it ran very rough. Turned it off and towed to mechanic. He thinks heads/head gasket but he didn’t do any testing. How can I troubleshoot this? I figured I should start with a cylinder leak down test. Any other suggestions?

 

[jgue467]

Could pull plugs and check for coolant, I'd start with #3 (middle right side).

It is the most common starting point for leaks and cracked heads, it takes very little 'overheating' to crack a head on these, ask me how I know.

 

[gamefreakgc]

Odd that it failed so quickly. When it is running do you get any smoke out the exhaust? That's the easiest sign with a significant gasket leak. Sure does sound like it if you are losing coolant AND it is running poorly but it is an expensive repair if you cannot do it yourself so make sure you are absolutely sure before you spend the money.

 

[jwkiss0]

Odd that it failed so quickly. When it is running do you get any smoke out the exhaust? That's the easiest sign with a significant gasket leak. Sure does sound like it if you are losing coolant AND it is running poorly but it is an expensive repair if you cannot do it yourself so make sure you are absolutely sure before you spend the money.

I have not run it for even a couple minutes after the episode. I don't know if it would smoke if it ran longer, but none so far. The coolant leak was due to the radiator I believe since it was all over the hood and front of the engine. Last oil change they said the radiator was discolored and would probably need replacement in the near future.

 

[jwkiss0]

Could pull plugs and check for coolant, I'd start with #3 (middle right side).

It is the most common starting point for leaks and cracked heads, it takes very little 'overheating' to crack a head on these, ask me how I know.

I plan to pull the plugs and check them when I get it home. They wanted way too much money at the shop to do this work. I honestly think the guy working there wanted my 4Runner. He offered me $1,500 for it.

Did you pull the heads and do the repair yourself? If so, did you do one or both heads and did you go remanufactured or new?

 

[jwkiss0]

Could pull plugs and check for coolant, I'd start with #3 (middle right side).

It is the most common starting point for leaks and cracked heads, it takes very little 'overheating' to crack a head on these, ask me how I know.

Your 4Runner is super clean. I thought mine looked good but I think yours looks better. That is a sharp ride.

 

[gamefreakgc]

I have not run it for even a couple minutes after the episode. I don't know if it would smoke if it ran longer, but none so far. The coolant leak was due to the radiator I believe since it was all over the hood and front of the engine. Last oil change they said the radiator was discolored and would probably need replacement in the near future.

Oh I think I missed that part. I am aware of the discoloration that happens with the original radiators, that means the plastic is being stressed and about to fail. Kind of like if you bend plastic and it starts to turn white where you've bent it. I suspect it failed at the seam between the top of the plastic and the top of the fins on the inside edge as the coolant likely sprayed out (it is under pressure) and hit the fan and splattered about. Sorry to hear it failed so quickly but I suppose your mechanic did warn you about it.

I agree that it should not be ran in that condition. Replacing the radiator is a relatively simple job and only a few bolts. The only tricky part is taking the fan off the fan hub as it likes to move around as you try and get a wrench on it. If you can get a DENSO/Toyota replacement and new upper and lower hoses (don't reuse the old ones as they molded to the shape of the old radiator) you can get it up and running again at your house. I realize you did have it towed to the mechanic though so you might be on the hook to have him replace it. At least then we can see if the head gasket did indeed blow or if it was only the radiator.

 

[JBurt]

Loosing coolant is one thing, and you can run it without any coolant for a few minutes. I agree that the radiator replacement isn't a bad job, and a new koyo or denso isn't too expensive.

If you suspect a bad HG, you can get a combustion gas leak detector. Autozone has it as a loaner tool. It'll tell you for sure if you've got exhaust gases in your coolant system, which means you've got a bad HG.

Timmy just did a 7 part series on replacing a bad head gasket.

Here's the autozone link

https://www.autozone.com/loan-a-tools/loaner-blown-head-gasket-tester

 

[jwkiss0]

Oh I think I missed that part. I am aware of the discoloration that happens with the original radiators, that means the plastic is being stressed and about to fail. Kind of like if you bend plastic and it starts to turn white where you've bent it. I suspect it failed at the seam between the top of the plastic and the top of the fins on the inside edge as the coolant likely sprayed out (it is under pressure) and hit the fan and splattered about. Sorry to hear it failed so quickly but I suppose your mechanic did warn you about it.

I agree that it should not be ran in that condition. Replacing the radiator is a relatively simple job and only a few bolts. The only tricky part is taking the fan off the fan hub as it likes to move around as you try and get a wrench on it. If you can get a DENSO/Toyota replacement and new upper and lower hoses (don't reuse the old ones as they molded to the shape of the old radiator) you can get it up and running again at your house. I realize you did have it towed to the mechanic though so you might be on the hook to have him replace it. At least then we can see if the head gasket did indeed blow or if it was only the radiator.

I was actually planning to have the radiator replaced next week because it was a convenient time. Unfortunately it didn’t make it that far. Do I need to replace the radiator before I do any testing?

 

[jwkiss0]

Loosing coolant is one thing, and you can run it without any coolant for a few minutes. I agree that the radiator replacement isn't a bad job, and a new koyo or denso isn't too expensive.

If you suspect a bad HG, you can get a combustion gas leak detector. Autozone has it as a loaner tool. It'll tell you for sure if you've got exhaust gases in your coolant system, which means you've got a bad HG.

Timmy just did a 7 part series on replacing a bad head gasket.

Here's the autozone link

https://www.autozone.com/loan-a-tools/loaner-blown-head-gasket-tester

Thank you for the link. Do I need to replace the radiator before I can use the combustion gas leak detector? The engine did not want to run very well after the episode. Am I risking any further damage by running the engine to use this tool? Is this better or worse than a cylinder leak down tester? Do both give me the same answer? Thank you for the help.

 

[jwkiss0]

Thank you for the link. Do I need to replace the radiator before I can use the combustion gas leak detector? I am assuming the engine needs to be running to use this tool?

I am new to the site. How do I find the videos Timmy put together on replacing head gaskets? Please don’t say the search tool because I don’t seem to have much luck with it.

 

[thegipper]

His videos are posted on youtube and can be found here.

I would replace the radiator, refill the system then you can try the combustion gas tester. Keep in mind that the fluid will only change color if the the leak is pretty bad.

Keep an eye on the temp gauge and don't run it back into the red and you shouldn't do any further damage. . A leak down test looking for bubbles coming out in the radiator is a more reliable test for a bad head gasket in my opinion. Timmy has a video on how to use a leak down tester also.

Good luck

 

[gamefreakgc]

I was actually planning to have the radiator replaced next week because it was a convenient time. Unfortunately it didn’t make it that far. Do I need to replace the radiator before I do any testing?

Yes because if there's air getting in the cooling system through a leak in the radiator you cannot do a coolant system pressure test or a combustion gas leak test. At this point you know it's not any good so it has to be replaced either way.

That's a bummer you had planned for it but the radiator had other plans. I had that happen to me with the clutch on my old Toyota. I noticed a crack in the clutch bracket and was starting to deform. Found a shop that would repair it and while driving there the bracket broke and fell on the carpet. Kind of hard to drive a manual transmission without a clutch pedal.

 

[jwkiss0]

His videos are posted on youtube and can be found here.

I would replace the radiator, refill the system then you can try the combustion gas tester. Keep in mind that the fluid will only change color if the the leak is pretty bad.

Keep an eye on the temp gauge and don't run it back into the red and you shouldn't do any further damage. . A leak down test looking for bubbles coming out in the radiator is a more reliable test for a bad head gasket in my opinion. Timmy has a video on how to use a leak down tester also.

Good luck

Thank you for the link. I have watched his videos before. I used them to fix the door lock actuator. He does a great job. Do you know of a good source for the radiator?

 

[jwkiss0]

Yes because if there's air getting in the cooling system through a leak in the radiator you cannot do a coolant system pressure test or a combustion gas leak test. At this point you know it's not any good so it has to be replaced either way.

That's a bummer you had planned for it but the radiator had other plans. I had that happen to me with the clutch on my old Toyota. I noticed a crack in the clutch bracket and was starting to deform. Found a shop that would repair it and while driving there the bracket broke and fell on the carpet. Kind of hard to drive a manual transmission without a clutch pedal.

That’s very aggravating when that happens but what can you do? I drove a manual for a long time and it is very difficult without the clutch.

 

[jwkiss0]

Yes because if there's air getting in the cooling system through a leak in the radiator you cannot do a coolant system pressure test or a combustion gas leak test. At this point you know it's not any good so it has to be replaced either way.

That's a bummer you had planned for it but the radiator had other plans. I had that happen to me with the clutch on my old Toyota. I noticed a crack in the clutch bracket and was starting to deform. Found a shop that would repair it and while driving there the bracket broke and fell on the carpet. Kind of hard to drive a manual transmission without a clutch pedal.

I'm wondering if there is any real reason to bother testing? I would have to rent/buy a gauge. It seems like it has to be heads or head gasket. I think I should just start taking it apart and plan for the heads/gaskets and not bother testing. What are your thoughts?

 

[nissanh]

YOu cna check compression leak into the coolant easily without any tools.

DO this on a COLD engine. open the radiator cap and start the engine, if you see continuous bubbles (a bubble every 2 seconds or so) then there is a bad head gasket.

On a HOT engine (NEVER open the radiator cap): Go to the reservoir and pull the plastic cap up while keeping the hose inside the coolant. look for bubbles.


I once heated my 5vzfe but the needle was 3/4 the way so never hit the red zone. This happened heading uphill. I quickly pulled over and allowed to cool. It has been 12 years and no significant loss of coolant to worry or no white smoke. So you might not blew the head gasket. Yours happened at a stop, correct?

 

[gamefreakgc]

I'm wondering if there is any real reason to bother testing? I would have to rent/buy a gauge. It seems like it has to be heads or head gasket. I think I should just start taking it apart and plan for the heads/gaskets and not bother testing. What are your thoughts?

I'm not entirely convinced your head gaskets are ruined. I have also overheated my engine and has been fine for years. The radiator has to be fixed either way and the repair has little overlap with the head gasket so it's not like you are saving time by doing both together. Fix what you know is broken or have the shop do it if space and tools is an issue.

 

[mtbtim]

The fact the engine was running poorly after the radiator failed isn't a good sign. The question is, did the radiator fail because the engine got too hot, or did the engine overheat because the radiator sprung a leak?

Anyway, you're going to need a radiator regardless so I'd start with that. After you get the radiator replaced and coolant refilled, I'd give the engine a start and see where you're at. If it's still running rough or spewing smoke out the tail pipe, you either cracked one of both of your heads and blew one or both of the head gaskets.

As a diagnostic tool, I'm not a fan of relying solely on those combustion gas detector kits. With by buddy Sean's rig, we confirmed he had coolant getting into the #3 cylinder using a leak down tester in conjunction with a cooling system pressure tester and the combustion leak detector didn't confirm the issue.


Here's our Radiator Replacement Video which includes installing a trans cooler.

<iframe width="560" height="315" src="https://www.youtube.com/embed/2nVbwe2t2T8?si=mICEl7PhR2OvXnbM" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe>


If you'd like an upgrade over the OEM radiator, Koyorad makes a nice one.

<iframe width="560" height="315" src="https://www.youtube.com/embed/4hS0pdMzyLo?si=_Js60sVXGrZBoxNp" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe>


Here's the video of [MENTION=102606]infamousRNR[/MENTION] (Sean) and I made confirming coolant was getting into the #3 cylinder.

<iframe width="560" height="315" src="https://www.youtube.com/embed/nelMt1UCEnU?si=WHytu92U2nX8sQjt" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe>


Finally, here's Part 1 of our Head Gasket video series. I unfortunately think you're going to need it.

<iframe width="560" height="315" src="https://www.youtube.com/embed/iSFpwnCuBDk?si=vdCW_8RSVxb25l9W" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe>

Good luck! If you need further help, you can contact me on this forum or on my Timmy the Toolman YouTube channel.

 

[jwkiss0]

YOu cna check compression leak into the coolant easily without any tools.

DO this on a COLD engine. open the radiator cap and start the engine, if you see continuous bubbles (a bubble every 2 seconds or so) then there is a bad head gasket.

On a HOT engine (NEVER open the radiator cap): Go to the reservoir and pull the plastic cap up while keeping the hose inside the coolant. look for bubbles.


I once heated my 5vzfe but the needle was 3/4 the way so never hit the red zone. This happened heading uphill. I quickly pulled over and allowed to cool. It has been 12 years and no significant loss of coolant to worry or no white smoke. So you might not blew the head gasket. Yours happened at a stop, correct?

Sitting still waiting in a school line.