Acura Integra coolant disappearing, no overheat

[Patrick Smith]

Hey folks, after having that crank/no start issue at the first of the year on my Integra that turned out to be the distributor, I’m back now with another issue.

For several months now my car has been losing coolant. I have not seen any traces of leaking coolant in or around the engine bay. Did not see anything underneath the car when I last changed the oil a few weeks ago. I suspected the radiator cap might be bad, so I just swapped that out with a new OEM Honda cap last week. But it’s still losing coolant.

A couple of months ago the coolant got low enough that the temp needle started to rise above the usual spot while sitting in a drive-thru line. It did not actually over heat, but had I sat long enough it might have. After I started driving, the temp came back down to normal. I topped off the radiator with my usual 50/50 mix and the temp needle has not gone above normal since then.

On Saturday I was pulling out of my subdivision, engine still cold, and I thought I saw a puff of white smoke in the rear view mirror, so I suspected a blown head gasket. While my car was down with a bad distributor, I did a compression test and the numbers were fine. Have never done a leak down test, though. However I checked my oil cap and spark plugs today for any milky, foamy residue, and did not find any. Oil on the dipstick looks good and is at the full level.

Today I also tried pressure testing the cooling system. I put 16 PSI on the system, and noticed the needle started to drop immediately. It didn’t drop as fast as in Eric’s video about diagnosing an overheat problem, but it was definitely dropping, getting down below 7 PSI within a matter of minutes. With the system pressurized I checked around and could not find any visible leaks anywhere. I even removed the spark plugs again to see if that made any difference in how fast the pressure dropped – it did not. I listened and thought I could hear pressure escaping around the radiator filler neck. But again I don’t see any liquid shooting out.

Is it possible that with the engine hot that coolant could be escaping somewhere around the radiator neck/cap, yet not squirt out as a liquid while the engine is cold and the system is under pressure? The pressure tester I used is an EverTough 67085 kit, with the adapter to fit my radiator. I also got a MotoRad MT-300 tester, but it did not have the proper adapter. But I tried the MT-300 tester with the adapter that came with the EverTough kit, still the same results. Could the adapter be faulty in some way? It’s all metal construction (the adapter) and seems to be in good shape.
[b][u]
A little history on the cooling system servicing of my car:[/u][/b]
March 2004: replaced OEM radiator with cracked end tank with a CSF replacement unit, which is still in the car.

May 2008 and the following months: damaged heater core pipes in the process of pulling engine out and putting it back in (pulled engine out to replace lots of stuff at 270,000 miles). Had coolant leaking inside car, bypassed heater core for several months until I could replace it. Also replaced both radiator hoses shortly thereafter.

November 2008: replaced heater core, and also replaced every single other coolant hose in the entire engine bay with new OEM Honda, because I was chasing various coolant leaks at hose connections. So every coolant hose in my entire engine bay is less than 5 years old, with less than 60K miles on it.

As of today, the car has 328K+ miles on it. Cylinder head has never been removed from engine. I’m smelling coolant inside the car, even after the car has been sitting in the garage for over 24 hours, but I haven’t found any signs of wet carpets anywhere near or underneath the heater core and dashboard areas.

Any other suggestions would be great. If it’s just the radiator itself that needs replacement (it’s nearly 10 years old now, and cost only about $110 new) then I’ll gladly do that because that will be a heck of a lot easier than replacing the head gasket.

Topic

[MARK FELDSTEIN]

You may have actually have found your leak at the neck of the radiator which is not an uncommon spot to find them. If the pressure is escaping from the top of the radiator, at 16PSI it exactly be bubbling up coolant to blow out the top end of the system. So that hissing may be it.

Aside from that, if it is the filler neck, once the engine heats up it may be losing coolant there and it’s evaporating before you can find it as it could also be doing elsewhere in the engine.

Check your thermostat housing for leaks; hoses and clamps, you can spray some soapy solution on hose connections and look for bubbles that would indicate air leak. Check all the hoses, not just a couple, and also the inlet and output hoses and clamps on your heater core. Smelling coolant inside the car could be a leak from the heater core so check the floor for dampness and the hoses in the engine.

I wouldn’t replace the radiator until you prove it’s leaking.
Mark

[Patrick Smith]

But if it’s losing pressure at the filler neck, and the rad cap is brand new OEM, wouldn’t it have to be the radiator itself that’s the problem?

[exceptionalchris]

I agree with everything Sparks4184 has said. I would first check to see that you have hooked up the pressure gauge correctly. If in fact you did, and you are losing pressure from the rad neck. then yes replace the radiator.

[MARK FELDSTEIN]

As I recall some radiators, newer and older ones, have the neck (upper hose fitting) and lower hose fitting soldered or brazened. Constant vibration can cause that solder joint to develop microscopic cracks. The new cap wasn’t a bad idea at all, but I’d retest it and as Chris said (below) make sure your gauge is properly hooked up. And if it’s the neck that’s leaking, yep, replace the radiator which is a pretty straightforward job that ECTG has done a nice video on.

But if it’s not the filler neck, test onward ! You’ll no doubt find the coolant leak cause it’s gotta be going somewhere. I’m a little suspicious of your heater core too based on the history you mentioned.
Mark

[Patrick Smith]

The radiators on these cars have plastic end tanks, upper and lower hose fittings, and filler necks.

So I drove the car to work this morning. After getting going, I did not smell any coolant inside the car. In fact I never smell it inside the car while driving, only after it’s been sitting several hours. I even drove with the heat on full hot, but did not smell any coolant smell through the vents. Car drives normally, accelerates normally, and also still gets the usual 28-30 MPG fuel economy. The engine burns 1 quart of oil AT MOST in 6,000 mile oil-drain intervals.

After I got to work I popped the hood and looked around. No evidence of coolant leaks anywhere. No smell of coolant whatsoever. With the engine running I also did not see any white smoke or any other smoke at all coming out of the tail pipe, but of course that was just with the engine idling.

I’ll run some more of these checks with the system under pressure tonight. Might also go back to the auto parts store and see if they have another kit just to rule out this one being faulty.

A user on another board mentioned that a rough idle on cold start that settles down could indicate coolant making it into the cylinders. The engine does stumble a bit sometimes on cold start, but after a few seconds settles at the usual cold RPM of 1500-1800 depending on ambient temps. I had assumed this was my FITV as it’s never been serviced or cleaned, but could that also be the HG leaking into the cylinders?

Here are some pics of my spark plugs and also looking down the plug tubes. Plug 1 is on the right, 4 on the left. Not sure about the residue on the threads of #3 and #4, but the plug tips themselves look pretty normal to me.

[IMG]http://img.photobucket.com/albums/v38/PatrickGSR94/MyIntegra/null_zpsf1210e11.jpg[/IMG]

Cyl 4
[IMG]http://img.photobucket.com/albums/v38/PatrickGSR94/MyIntegra/IMG_9171_zpsfbac1ec6.jpg[/IMG]

Cyl 3
[IMG]http://img.photobucket.com/albums/v38/PatrickGSR94/MyIntegra/IMG_9172_zps210c488c.jpg[/IMG]

Cyl 2
[IMG]http://img.photobucket.com/albums/v38/PatrickGSR94/MyIntegra/IMG_9173_zpsfe6ef468.jpg[/IMG]

Cyl 1
[IMG]http://img.photobucket.com/albums/v38/PatrickGSR94/MyIntegra/IMG_9174_zpsc2afe623.jpg[/IMG]

[Patrick Smith]

Okay the pressure tester I had, specifically the adapter piece, was definitely faulty and leaking. I swapped out the kit for an identical kit today, tried it on my wife’s car first, and it held pressure perfectly. So I put it on my car, and it’s been holding 16+ PSI perfectly the last 20 minutes or so.

Today I didn’t notice any coolant smell inside the car or in the engine bay, and the coolant level in the radiator this evening appeared to be the same as yesterday. Reservoir coolant also appeared to be the same as yesterday.

I’m thinking maybe there was some air in the system when I topped it off last week and put the new radiator cap on. The air must have worked its way to the top of the radiator and made it look like the coolant level dropped. Not sure why I thought I saw a puff of white smoke in my rear view mirror the other day. Maybe it was my imagination. 😛

*edit* pressure has still been holding above 15 PSI for nearly an hour now. Removed spark plugs, no change in pressure. Sprayed soapy liquid on all coolant hose connections, saw no bubbles anywhere.

*edit 2* also just ran the engine with the radiator cap off, did not see any bubbles coming up in the coolant.

[MARK FELDSTEIN]

Nice going Patrick ! I’d give you an “A” for diagnosing a NTF (No trouble found). Sorry to hear you had a bad tester, but OTOH, I’m glad you didn’t replace your radiator. At a minimum, this goes to prove thorough testing for a problem pays off in more ways than one. Also, it reminded me that tool rental (or borrowing) places don’t always test, calibrate or otherwise maintain the tools they loan out. It also goes to show that it’s a good idea to burp your cooling system when you add coolant and to drink a cup of coffee BEFORE leaving for work. ;>)

I don’t think there’s anything wrong with your plugs and if you really want to prove this is an NTF, you could do a power balance test or a compression test. I recall Eric has done videos on both.

Happy Motoring !
Sparks

[Patrick Smith]

Yeah I ran a compression test back in January when my car was sitting dead with a bad distributor – was actually the first time I ever performed a compression test on this engine with well over 300,000 miles. All numbers were within spec at that time. I guess I could do it again.

I always do my best to purge air from the system whenever refilling or flushing the cooling system, including opening the bleed screw where the upper hose attaches to the engine head. But this last time I topped off the radiator, it took quite a bit to fill it up. I squeezed the upper hose to get bubbles out, and opened the bleed screw, but I guess I did not completely rid the system of air pockets.

[college man]

Glad it a simple fix.keep us posted if things change. 😉

[Patrick Smith]

Well, started the car this morning and it had quite a hard time getting up to cold idle speed. Then as I was heading out I saw quite a lot of white smoke billowing out the back of the car.

So the HG must be blown. Not sure why the cooling system would have held pressure with the pressure tester, but the HG has got to be blown with all that white smoke coming out.

I did notice that after the car got up to operating temperature, I never saw any more white smoke. Could there be a HG breach that sort of “seals up” when everything gets hot?

I also plan on replacing the lost motion assemblies (LMA’s) for the VTEC rocker arms as those have needed replacement for several years now. Honda updated the design of those to a spring style, and my engine still has the old hydraulic ones which are prone to failure.

[Its me]

I have seen it where HGs leak when the car heats up

Cheers

[Patrick Smith]

lol ninja post edit? 😛

I did not get a whiff of the smoke, just saw it coming out behind the car as I was driving, and also saw it blowing to the side while at a stop sign. It was not blue or black, though, so I would not suspect oil or fuel burning. Have not checked coolant level yet, need to wait until the engine is cold.

I’ll do a compression test this weekend and probably also rent a leakdown test kit.

Something else I have noticed recently is that when removing the radiator cap (engine and coolant cold, or cooled down anyway) I hear what sounds like pressure being released into the overflow tank, making bubbles in the overflow tank. Is that normal? I don’t ever recall hearing anything like that before the past couple of months or so.

My car will be sitting at the office tonight as I commute by bicycle a couple times a week, so I won’t really be able to look at it further until the weekend.

[Patrick Smith]

Still haven’t run the compression or leak down tests yet.

I put the coolant pressure tester back on the radiator today, pumped it up to 16 PSI and let it sit. 3+ hours later it’s down to 14 PSI. So it’s losing pressure but verrrrry slowly.

My theory is there is a breach in the HG but only very small, such that residual pressure in the cooling system after driving the car and cooling down, forces small amounts of coolant into one of the cylinders, which then gets burned off when the car is first started the next day. But then for some reason it doesn’t seem to burn any after the car is up to temperature.

[Patrick Smith]

So I just did a compression test with engine at operating temp. 94 GS-R B18C1 with 329,000 miles.

First Test – – – Second Test
Cyl. 1 – 237 – – – 249
Cyl. 2 – 235 – – – 242
Cyl. 3 – 267
Cyl. 4 – 267

I started second guessing my test of the first 2 cylinders which is why I tested those a second time.

Factory spec says nominal compression should be 270 with a maximum variation of 28. Max variation between cyl 2 (2nd test) and cyl 3 (1st test) is 25. So it looks like it’s not really very conclusive.

Unfortunately there are no parts stores in town that can rent out a leakdown tester. I can buy one at Harbor Freight for $40, so I’m trying to decide if I even need to bother with that test or just go ahead and pull the head and replace the HG.

[Author]

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