Hi - I have a 95 Camry DX Sedan 5 speed manual with 2.2L and 380K miles
I was driving on the highway when I felt what seemed like either a failing fuel pump or clogged fuel filter. The car would hesitate and then catch again.
It seemed worse going on an incline and better on a decline (thinking maybe fuel filter). I wanted to get off the highway because it was rush hour and I was about 2 miles from an exit. When I took the exit it sounded like the car might be knocking and pinging (making me think gas again) so I pulled over to a safe spot and called AAA.

When I got home I checked for spark and it seemed to be orange (car cranks fine). Coil cold resistance was good. But I had a coil replaced 6 years ago that had an orange spark and good cold readings. So I thought maybe it was just the coil again. So I decided to pull out the distributor and change it. Well today I looked in the Throttle Body and noticed a light trace of coolant (or at least thats what I think it is).

And Im saying how the heck does coolant get into a TB. After researching many hours I found out that the IAC has an inlet and outlet pipe for coolant to possibly heat up the throttle plate? So my guess now is that the 24 year old gasket inside the IAC is shot and was letting in coolant.

I have had a minor coolant leak for years and could never find an external leak and thought I had a small head gasket leak even though the car never overheats, never blows white smoke and the oil looks fine other than being dirty as Im sure I have a sludge coating under my valve cover. I never knew coolant went through my IAC valve.

Another thing that makes me think this is the issue is that I read I could have been leaking coolant from my radiator cap as it would evaporate before you would ever see any signs of coolant escaping from the cap.
Well I did put on a new cap not too long ago so Im wondering if the new cap sealed so well now it helped speed up the leak in the IAC gasket.

Im surprised Toyota would use such as poor design. Why not just have a channel in the TB or a dedicated hard line going through it to heat throttle plate.

So my questions are - did I kill my car? Do you think any of the coolant got into the cylinders? What are my next steps?
It doesnt sound like I need a new IAC valve but definitely a new IAC gasket. Should I replace the 2 coolant lines into the IAC or should I just bypass them by putting a loop from inlet to outlet? I assume removing the TB is the easiest way to access the 4 IAC screws? What should I be spraying inside the TB/intake to clean it out?
Anything else I should be testing for?

Thanks for your help
I hope my car isnt dead I really loved it
Kev

 

Great post!

Have had issues of fixing or replacing leaky metal radiators on equipment and finding the system still losing coolant. The now sealed coolant system was generating more internal pressure and showing up other leaks at the higher pressure.

The IAC valve is connected to the coolant system.

The IAC gasket (available aftermarket) goes between the IAC valve body and throttle body to make it air tight. If leaking, there must be something wrong with the coolant side of the valve. Not sure this area can be repaired.

Are the small hoses leaking?

You stated you found coolant inside the throttle body. Compare what fluid you found to whats in the radiator for feel and smell.

Disconnecting might result in idle issues including major surging of the idle. Have experienced this on other cars with IAC valves and coolant flow issues.

You can buy just the IAC valve for around $150 (aftermarket) Most often the valve servo fails then the valve leaks. IAC valve failure is rare. Take off the throttle body and work from there.

If getting a new IAC get the right one. As in federal or California emissions and stick shift or automatic.

Excess coolant in the engine could cause engine damage but doubt this is the case here. However, over time the coolant damages emissions converters.

If your going to clean the throttle body use a throttle body cleaner safe for plastics. The IAC valve is plastic.

Read up removing the IAC valve as there might be some special screw head on the body but forgot if yes or no.

If wanting to replace the two small hoses Toyota may be the only source for the molded lines.

 

Thanks toyomoho
i do believe it is coolant after checking, feeling and smelling. It kinda makes sense now that when I was going up an incline I was using more throttle and more coolant must have been getting in through the IAC passage and when I was going downhill I probably had my foot off the accelerator so with the throttle plate closed it wasnt getting any coolant. Hopefully it was only enough coolant to make it run rough.

I did buy the 2 smaller hoses from Toyota - yes I dont even bother looking for any of the small hoses elsewhere, Toyota always has them and theyre not too expensive. I wasnt sure if they were leaking but felt they were brittle and looked like seepage but that could have been from oil as well from my distributor but I put a new O-ring on that now. I probably should have also bought the large vacuum line that is on the IAC as well as it feels as if its hard as a rock.
I have had good success getting hoses off with a little quick heat from a heat gun.

My plan is to remove the throttle body and IAC valve and clean both really good. Reinstall with new gaskets and hoses and hope for the best.
How long do you think it will take for the car to clear of the excess coolant and start running at a normal idle?

Good to know about the specs for CA vs federal in case I need a new IAC. Not sure what you mean by something could be wrong with the coolant side of the valve? Do you mean the gasket could be fine and than that would mean theres an actual mechanical failure of the valve? Im thinking the gasket is 24 years old and must be bad but who knows!

I hear the 4 IAC screws can be trouble to remove. I do have a impact screwdriver that I could utilize.

Thanks again for the help

 

The valve has 3 separate chambers. Two smaller ones for air flow (in and out of the valve) and one larger one to seal the coolant camber. Could be the gasket between an air chambers and coolant camber has failed or somehow a hole in the metal body.

See link below. Two small gasket ports and one large one.

Please post back with what you find when you take the IAC valve off.

. https://www.ebay.com/i/151788639927?...yABEgJ83fD_BwE

 

So I got everything apart. The impact screwdriver for the 4 IAC screws was a must. There was no way they were coming out without that.

I made one mistake - I wasnt thinking on all 4 cylinders so to speak! - I cleaned the TB before I took off the IAC so I throttle body cleanered any tell tale
signs of coolant seeping across the passages inside the IAC. The gasket itself looked pretty darn flat almost as thin as the metal in the area that separates the coolant from the air. Hopefully this is my problem otherwise I might be in bigger trouble!

Im going out to buy new gaskets and some small worm gear clamps for the new hoses.

Before I close up the TB should I be trying to dry out the inside of the intake plenum? Its not puddled or anything but I can see a shiny film of coolant.

If not how long would it take to burn off the existing coolant?

 

I personally would not bother cleaning the plenum. If you stopped the flow of coolant and there are no puddles then it should be good enough.

Suppose you could try to mop out the plenum with a cloth well secured to a rod. Could spray a cleaner on the cloth and scrub.

Unless a flood of coolant in the intake the coolant should have be burned off as you drove. Thus good to go.

One other to consider is the coolants effect on the O2 sensors. Coolant can poison sensors.

Suggest fixing the IAC and then watch the coolant level.

Unless the engine was overheated the head gasket should be OK.

Could have been bad gas. Did you check the gas filter sock in the tank? The can filter inside the engine compartment seldom plugs up.

Can add a dye that glows under black light to the coolant and after driving check for signs of said dye.

 

I was able to get my gaskets today. Had a very hard time finding them at the local auto stores. I finally found them at O'Reillys.
They gave me FelPro 60687 for the TB (its paper as opposed to the original metal one) and FelPro 61085 for the IAC gasket. The package says
its for 1997 - 2000 but the shape matches my 95 perfectly, hope its not a thickness issue.
Hope to have it put back together tomorrow.

Do I need to worry about pulling the spark plugs at all and cleaning them?
And do I need to give the car an oil change? Is there a chance some coolant is in the oil now?

Thanks for the advice

 

Doubt there is coolant in the oil. The internet has videos and photos for checking for coolant in engine oil.

If your concerned about the plugs, just change them.

 

Well I finally got the car back together. Amazing that I couldnt find 5 minutes to work on it over the weekend or maybe I knew I was delaying the inevitable.

Yes I think the car is dead. I think that "knocking & pinging" I heard thinking not enough gas was actually my rods/piston.

I had my wife start it and it sounded like knocking coming from the engine.

I didnt see anymore antifreeze in the TB but it does look like something might be coming out of the hose out of the valve cover into the throttle body.
I did pull & check one spark plug before starting and it was dry as a bone - looked good.

I wonder if an oil change would help, and maybe pulling all the plugs and spraying some wd40 down the tubes and then cranking it?

I definitely think the IAC gasket was bad but maybe too much antifreeze made its way into the engine.

The oil does smell a little funny to me as well.

Any suggestions? Just a sad night

 

One quick question since I am hoping its not really dead -

I can remove all the spark plug boots and the engine cranks fine - if I had an issue with a rod or piston would this be the case or would it not crank?
And when it cranks there are no other weird noises being made - only the sound of the engine cranking.

Is there any possibility something is in the cylinder (antifreeze) an hasnt destroyed it yet but when it tries to actually perform combustion it is making this
knocking noise?