2006 4.0L cam position sensors leaking coolant

2006 Tacoma 4.0L, both camshaft position sensors leaked coolant. I replaced them both and the leak stopped so far. It's only been two days since replacement. However I'm not sure there is supposed to be coolant there. When the old sensors were removed there was brown/tan oil on the backs of them. There is no oil in the coolant or vice versa. Thoughts?

 

I have not dealt with this yet, but was curious. Using the post I found here, they are farther down than I expected and maybe not that far from the water pump and/or all of the other plumbing north of the cam sensor(s).

https://workshop-manuals.com/toyota...or/component_information/locations/page_3643/

 

I don't see the camshaft position sensors in that diagram. They're up near the VT sensor and oil control sensor. Top of heads, as close to the valve cover and forward as it can get. The parts house I got them from called them camshaft position sensors but idk. Looks like the boxes they came in aren't in my trash can, looks like I emptied it since then.

 

Damn, I paid over $100 each.

 

Check the coolant lines that route into and out of the throttle body. Those are your likely culprit.

 

The coolant was definitely coming out of those sensors. The right sensor is no where near any coolant lines. Both sensors looked the same as the picture above. The coolant lines for the throttle body are in the center of the engine. The throttle body had to come off to access the left sensor and it had no visible signs of leaking. Basically I'm trying to find out if there's supposed to be coolant at those 2 sensors. I'm wondering if there's a coolant leak between the timing cover and the engine block putting coolant where it's not supposed to be.
I've searched all over the web but I can't find any information on this exact type of leak, but I may just be typing the incorrect words in my search, Idk.

 

No coolant is related with that sensors operation. If you have coolant coming out of that sensor, then you also have coolant in the oil pan.



Right next to that actuator port, is a coolant fitting and line. You can see the hose in the picture. Investigate there.

Also, the other head has a hose of similar size. One of those hoses around that area, is either leaking onto those sensors, or another hose.

Are there coolant traces anywhere else in the engine bay, that can lead to a source?

 

Sorry for the incomplete diagram.

If you paid $100.00 - you may have sourced from a dealer or purchased a Denso brand from somewhere else. At Rock Auto Denso part # 1961001 is $74.79

When it comes to electrical/electronic - you want OEM. Denso makes that type of equip. for Toyota. The dealer cam sensor is just a repackaged Denso, sold for less($74.79 at Rock Auto).

The brand you pointed to(Facet) is an off-brand. I hope it doesn't die early like a lot of off-brand electrics do.

 

I hate to be argumentative sounding, but there is no oil in the water and vice versa. It doesn't make any sense to me whatsoever. There was oil on the back of the sensor where it goes into the timing chain cover but no coolant that I could see. I didn't look at any hoses near either sensor because it just looked really obvious it was coming out of the sensors. I'm going to have to take another look at it for the hoses you're referring to. I definitely think you're on to something though because after reading your comment and looking at the picture more closely I'm not so sure the coolant was coming out of those sensors. The only traces of coolant to be found that I saw where these 2 sensors and the inner fenderwells that had coolant in a spray pattern like a line, similar to a water squirt gun.

When I posted that Rock Auto part it was just a reference so people would know exactly which sensors I was referring to. I don't recall the brand of the sensors I purchased, definitely an off brand and not a Denso, unfortunately. Toyota wanted over $135 each, I found them on the web as cheap as $20, but I was trying to get it done that same day. Now I'm expecting problems from those sensors that I bought. Bummer.

 

Check also the underside of the water pump. There is a weep hole there.

 

I'm back from vacation and I drove the truck a little bit and both sensors have coolant on them. I didn't fix anything when I swapped the camshaft position sensors. I was rushing myself and wasted money because of my poor choice to rush. Using a ratchet extension, I can hear the water pump bearings rattling around. But the water pump is in the center of the engine and these sensors are on the top. I don't know where the water pump weep hole is on this engine yet but all the previous weep holes I've seen have been on the bottom of the water pumps. Maybe it's those coolant tubes on the throttle body, I don't know yet, but I'll definitely stop throwing parts at it and figure it out.

 

It needs a pump. The coolant leaks onto the pulley and belt and gets flung around

 

Have you seen a water pump leak on these trucks? I have not. I'm sure the water pumps go out. I can hear this water pump going out. It just seems odd to me there's water up that high from a water pump is all.

Thank you for the reply.

 

When the water pump bushing goes bad and gets noisy it allows coolant to leak out past the shaft. Take the serp belt off and see how play is at the pump pulley. Get a pocket mirror and a flashlight and look below the pulley, ill bet you can see coolant dribbling out

If you've got a mysterious coolant leak and a bad water pump dont overthink it. Replace the pump

 

I don't get it. Coolant might be "self-sealing" in that a leak may not always be huge, because it can dry to a crust that kind of stops the leak later on.
But it is still a tell-tale sign/evidence that something as leaked, so it must be found/traced and then fixed, so it doesn't get worse.

Leaks generally flow from top to bottom (gravity) and front to back, because the car accelerates/moves forward and has wind blowing in through the radiator grill.
One way to find a leak is to clean the area and then see what comes back. I haven't messed with UV leak detection dyes, or leak detection spray. I hear with dye put in the oil, that the oil must be changed after using it to find a leak. Which adds cost to the job (oil change). But that is about oil leaks and not coolant.

I think drivetrain speed sensors (such as camshaft position) either go in a wet oil hole, or dry hole. And are magnets. That work by having a signal measuring the teeth on a spinning wheel.
Which means they're not related to coolant.
So a camshaft position sensor, measuring a camshaft spinning, in a valve cover, should not have coolant.
Or any other similar sensor, such as Engine Speed Sensor.

It is probably not good to leak coolant into wiring, if that ever happens. It can get wicked up by the wire into other places you don't want corrosion.
I am not sure if this coolant leak is something you can trace by doing a pressure test of the system with a tool.
On some cars, frequent timing belt services including water pump replacement are considered regular routine maintenance. I don't know about Tacoma's.

Water pumps (just one part of a big cooling system) usually seal onto the engine with a gasket or an O-ring, both of which I can imagine can deteriorate over a certain number of years and miles.

 

My uv leak tester came with additives for oil and coolant. You could try a coolant pressure test which pumps up pressure into the cooling system and will pretty much always find the leak source. It helps to watch the suspect area as you pump, you never know if the leak will show at as little as 5psi, or may need 15psi to show. I’ll bet you can rent one from a parts store if you don’t want to own one.

 

I have.

 

Ok great, thank you.

 

Look at your water pump pulley from the side so you can see the right and left sides of the pulley straight line is sight. If your water gun squirt is alone that same line, then your water pump is leaking onto the pulley, then flinging coolant off. From there it can end up anywhere pooled up looking like a leak there. Another way to confirm a failed water pump is to take its belt off, then give it a spin, pull on it. It should spin without notchy binding or feeling like it’s bearing is destroyed. There should be no play on the shaft in and out, up and down, side to side. It should feel like an alternator pulley except it won’t spin as freely.

 

I can hear the water pump bearing rattling so I know it's going out. It just looked like the coolant was coming out of these sensors, but I'm now positive it isn't. I have a Aisin water pump on it's way to me. Thank you for the reply.