Coolant leaking - replace water pump, radiator, or both?

[przm]

My truck: 2005 4Runner Sport, 4x4, v6

Backstory: I took a roadtrip from San Diego to Denver and back at the end of April of this year. When I was passing through the middle of nowhere Arizona, I noticed my truck overheating. I topped the radiator off with water and made it home with no more overheating issues. As soon as I was home, I did a radiator flush and refilled it with the red Toyota long life coolant that I picked up from the dealer. I checked the levels over the next week or two and it wasn't dropping from what I could tell.

Last week (4 months later) I had a similar issue. I was on my way to work and got stuck in massive traffic. I noticed my temp getting really hot (it maxed out a few times). I did my best to get off the freeway asap, but there was a 10 car pileup and traffic was not moving. When I would get going, maybe 5-10 MPH, the temp would drop, but as soon as I was sitting still, it would rise again.

I made it to a gas station, let the truck cool, and filled it up with .5 gallons of water. While I was had the hood open, I noticed some dried crusty coolant residue on the front of the engine block and some oily residue to the left of it (sorry, I wish I could provide more technical terms of where the residue was, but there's lots of photos below). The research I did on here and other forums leads me to believe that it's the water pump and/or the water pump seal going out. I have been topping off the radiator level this whole week and it's definitely leaking, but not very much.

I did an oil change today and while I was underneath the truck, I noticed some crusty red residue on the left and right sides of my radiator (definitely worse on the passenger side though). And a whole lot of coolant stains under the engine and on the skid plates.

I couldn't find many good pictures of this issue on other 4runners, so I did my best to provide some good photos of the issue and hopefully help out some other members in the future that might experience this issue. My questions to the forum are this...

- What is the issue? Should I replace my water pump, radiator, or both?
- What is the oily residue to the left of the crusty coolant on the engine?
- Since I assume i'll be replacing the water pump, what else should I replace while i'm in there (seals, gaskets, etc?)
- Other threads recommend getting the water pump from the dealer, but should I get the radiator from there too (if needed), or is a 3rd party okay? Which do you recommend?

 

[sr5hi]

First thing to do is find out exactly where your leaking coolant from. You need to pressure test the cooling system.

 

[ZimDoc]

First step is pressure testing the cooling system and pin pointing where the largest leak is. From there replace that part and pressure test again after filling the cooling system. If there are no other leaks be careful because other leaks may only show up when the engine is hot.

From what you have shown both the water pump and radiator needs replacing. Possibly other items too.

 

[hearno]

If it was my truck, I'd check the head gasket first since you stated you maxed out the temp needle several times. I wouldn't put a new water pump and radiator on it to be told you need another couple thousand to get it right.

 

[BRossman]

Start with the water pump and radiator. The 1gr engines will have a cold soak misfire if it is a blown head gasket from my experience.

 

[hearno]

Start with the water pump and radiator. The 1gr engines will have a cold soak misfire if it is a blown head gasket from my experience.

Correct, when it develops on its own. This is after a bad overheat, coupled with a known potential issue, I'd start with checking the worst case. His much does it cost to check the head, $100? Cheap insurance.

 

[przm]

excuse the noob questions, but how do I pressure test the system, do I need to take it to the dealer for that? Same thing goes for the head gasket, how do I test it?

 

[BlackWorksInc]

excuse the noob questions, but how do I pressure test the system, do I need to take it to the dealer for that? Same thing goes for the head gasket, how do I test it?

I don't mean to sound rude, but if you're not entirely sure how to do this; you may not understand/interpret the readings accurately.

If you Google the terms "How to perform a Cooling System Pressure Test" and "How to perform a Leak-Down Test" it will provide you with information on how to do both tests.

But first I have a couple questions, first being when you did your cooling flush did you use Toyota LLC (Long Life Coolant, aka Toyota "Red") or did you use Toyota SLLC (Super Long Life Coolant, aka Toyota "Pink") they are two different coolants and the Toyota SLLC is designed for the 4th gen 4Runners, while the Toyota LLC is designed for older Toyotas. If you're using Toyota LLC, it is not the correct coolant for the vehicle.

Second, did you properly "burp" the cooling system when you did your flush? When you drain the coolant out you create large voids of air in the system that do not bleed out just by topping the coolant off. If you didn't "burp" the cooling system you could be short as much as half a gallon or more of coolant which could easily cause an overheating situation.

Based on your pictures it appears your water pump & radiator are leaking, but as was stated above I would perform a pressure test to determine the cause(s) of the cooling system leaks and also a leak down test to rule out the head gaskets just in case as your are within the '03-'05 range of 4th gens that seem to have an uncommon headgasket problem.

 

[BRossman]

I've had very spotty luck with using a hydro carbon tester on modern head gaskets for small leaks....

You have to replace the water pump and the radiator as they are actively leaking and a pressure test will bleed off there first..

Then run the vehicle to operating temp, pull spark plugs and pressure test. Let it sit overnight and inspect for coolant intrusion in the cylinders.

 

[BlackWorksInc]

I've had very spotty luck with using a hydro carbon tester on modern head gaskets for small leaks....

You have to replace the water pump and the radiator as they are actively leaking and a pressure test will bleed off there first..

Then run the vehicle to operating temp, pull spark plugs and pressure test. Let it sit overnight and inspect for coolant intrusion in the cylinders.

I haven't had good luck with hydro-carbon testing the coolant either, we've played with using the smog machine at work; but it only works on really badly leaking headgaskets from what we've seen (though usually at that point you'd see bubbles in the radiator anyways.)

A cylinder leak down test seems to work the best in terms of diagnosing potential leaks, we've had the best luck with finding pinhole/small leaks by just running shop air into the cylinder on TDC with Intake & Exhaust valves closed and looking in the radiator for bubbles.

 

[hearno]

A cylinder leak down test seems to work the best in terms of diagnosing potential leaks, we've had the best luck with finding pinhole/small leaks by just running shop air into the cylinder on TDC with Intake & Exhaust valves closed and looking in the radiator for bubbles.

That's where my mind was at with this.