Maybe head gaskets...

[roarr]

Hey again guys,

Seem to be having bad luck with the Aurora lately. The AC pump finally seized and caused the engine not to turn over at all, had to bring another car to help jump start and even that took about 10 seconds of slow, slow cranking before it started up and tore off the serpentine belt. Before I replace the AC pump or go with a bypass belt I was going to check the head gasket to make sure that wasn't on its way out before I spend any money on a replacement pump. 

And so I bought a combustion leak tester. And it's not looking that great.

It's supposed to turn yellow if you have a leak but I cannot get it to change further than a light blue with a greenish tinge to it no matter how many times I pump it or whether the engine is cold or hot. I can breathe into the cylinder and cause it to turn a bright yellow so I know it's not defective. 

I don't get any signs of overheating even if the engine is run continuously for hours. There is a fairly obvious sweet smell to the exhaust but it's not the same kind of sweet (much less bitter) as what I'm smelling out of the coolant tank when the engine is hot. It's always done that since I got the car over a year ago. No white smoke, seems to smoke about as much as other cars; perhaps just a little more. No coolant smell present after the engine is run hard. Recently I have noticed the coolant level seems to drop slightly maybe every thousand kms or so, but I haven't actually measured any of this to verify it. I also replaced the radiator a few months ago with a brand new one.  

Here's a photo of one of the most recent tests I did. I don't know why the bottom cylinder did not change color during this particular test but the bottom shows the original fluid color and the top shows the color I keep getting, usually in both of the cylinders, when I press it onto the coolant tank. As I mentioned earlier I can't get the color to change any further which puzzles me.  In case you don't know how this particular tester works; the top compartment is the actual result, the lower compartment simply filters out other compounds that could affect the result. 

I have a feeling there's something else causing my issue and it's not the head gaskets, at least I hope they aren't!

[Randy T.]

Has your Aurora ever overheated? Does it overheat going up hills or over 45 mph? It's hard to spot bad head gaskets on these, oil in coolant or coolant in water or coolant out the exhaust is very rare.

Replace your heater core rubber hoses, replace your coolant crossover gaskets(water pump housing), if your coolant crossover gaskets have not been changed in 5 years,they are bad, same design on Ford intake coolant areas, same design on GM 3.8 lower intake gaskets, same on all '95-'03 Auroras, LX5 included.

[roarr]

Randy, It has never, ever overheated, at least since I've owned it. The engine is extremely cool running over 45mph or on hills, a bit under the center mark. As long as the car is moving the temperature is somewhere in the center, if I leave it idling for extended periods it creeps up a bit but nothing alarming. I had a radiator leak once but it never overheated even then as I always topped up the coolant for the two weeks or so it happened until I sourced a new radiator. I've never since gotten a "low coolant" message, I'd just open the reservoir every once in a while while checking other fluids and notice it's not at the middle mark where it was before, but just enough below to be noticeable.

I think it's definitely got to be something else leaking like you said. Heater core could be leaking but it wouldn't cause the smell in the exhaust right? No visible leaks on the interior but there is a slight smell sometimes when running the heater only while idling which could be coming from the engine compartment as I can smell it outside the car after I shut it down. A lot of coolant has been spilled inside the engine bay but this was months ago and it's already been washed down (plus almost everything is covered in oil from rustproofing yet I don't smell that burning).

I've started reading up on coolant crossover gaskets and that's what I think it is; I just don't know if there's some way to definitively confirm this so I don't go ripping it apart and wasting my time if that wasn't the issue.

Thanks for your help!

[rorafan]

Does sounds like a leak v. head gaskets esp. if it's not overheating. A leaking heater core will smell and/or drip INSIDE the car. Can also fog up the windows pretty good.

You can buy UV tracer kits with a UV flashlight and a small vial of dye you add to the coolant. Drive it a few days and then in the dark go over the engine with the light. Any leaks will literally glow from the dye. Not super cheap ($50 or so IIRC) but if you really want to be sure they can work wonders. If you're friendly with a local shop they may be willing to do this for free or very cheap.

You might also be able to tell if you clean the engine thoroughly and then visually check things over a few days later for signs of a leak.

[RCA1186]

Excerpt from northstarperformance.com:

"I've been told it's probably head gaskets. Could this be true?

Of course, you won't want to have the head gaskets replaced if it's not necessary. Many people don't get straight answers when it comes to head gasket diagnosis, especially when it comes to Northstars. While we strongly recommend having this work done if your car is a 2003 model year and older, as preventative maintenance, it may not be necessary quite yet.

Here are the most common signs of head gasket failure on a Northstar:

- Overheating
- High pressure build-up in the coolant surge (fill) tank, that remains when the engine cools off
- White smoke from the exhaust (condensation/water vapor is completely normal for any car)
- Coolant smell from the exhaust
- Engine temperature spikes during acceleration or climbing steep grades
- Coolant in the oil (this will turn the oil a milky white or light brown)
- Sudden severe oil leak coming from rear main seal area

One good test: make sure you have adequate coolant, and get the car on the highway and do a few quick acceleration runs. Get the car quickly up to 70 MPH (120km/h) and slow back down to around 30 MPH (50km/h). Only do this where it is legal! Repeat this process, monitoring coolant temperature. If you have the guage, the temperature should never normally run past the 5/8 mark. If you have the digital read-out, the temp should never hit the 240 degree F mark. If the temp keeps climbing to the point where it tells you "A/C off for engine protection" or "Engine hot - idle engine", or your guage passes the 3/4 mark, pull over immediately, let the car idle for a minute and shut it off. Let it cool down a bit, top off your coolant and make your way back home. At this point, keep your foot out of the gas as much as possible. Your head gaskets are blown / head bolts pulled.

The best test: get a "combustion leak test kit" available from Napa or Autozone. It will check for exhaust gasses being present in the cooling system. This test never fails.

Many repair shops are capable of diagnosing a bad head gasket but not all of them know how to deal with the Northstar. Did you know a Northstar can pass all the usual pressure tests, and still have a bad head gasket? This is due to the troublesome head bolts. This is why we recommend the method above for determining the state of your gaskets.

So what to do now? Well, for starters, DON'T use any type of quick-fix in a bottle. I'm sure you've read about miracle sealants that are designed for the Northstar and a bunch of other stuff on the market. All this will do is clog up the coolant passages. The guy who does your head gaskets won't appreciate the mess that will need to be cleaned out once he tears your engine down, and you won't like replacing your radiator and heater core. Of course it is never a bad idea replacing your water pump, checking the belt and tensioner, cooling fan operation (they do fail sometimes) and if in doubt, a new radiator. But a lot of the time, nothing but the head gaskets will need to be done.

If you have coolant in your oil, stop driving, period. Don't run the car at all. This can severely damage your engine. If you must move the car, make sure the oil is at the proper level and not too high.

If you are seeing moderate to heavy white smoke, don't try to start the car again- get to where you need to go and shut the car off. Especially if you have a 2000 or newer model- the engines are not as strong and have been snapping/bending connecting rods when coolant gets in the cyinders.

If you are getting exhaust gasses in the coolant (pressure in the plastic coolant tank), it is OK to drive the car providing you can keep your speed down to about 50MPH (80km/h) and you keep checking/topping off your coolant. No more sudden acceleration or passing, and stay away from long hills. Just don't overheat the engine. Regardless of what the owner's manual says, it's not OK to continue to drive without coolant- these cars have a limp-mode but it is not very effective. If you have overheated your engine, the oil-life-monitor will return to 0%. You should change your oil after overheating the engine.

[roarr]

rorafan, I've never had the windows fog up as a result of running the fan, I have it set to Auto all the time so it blows air onto the windshield most of the time, so I don't think it's the heater core leaking. No wet carpet or anything suspicious of that nature at all. The climate control works extremely well as the windshield never fogs up even with the AC not working. It's just the smell I notice if I put my face up to the vent. Thanks for the dye suggestion, I'll try that soon, I'm leaning much toward the leak side vs head gasket/bolts.

I'm noticing the problems only occur when the car is idling/under low load/light driving. There's no smell of coolant in the exhaust after doing WOT and driving for a longer period of time at higher engine load. The car gets cooler the faster I go, WOT included. No white smoke on WOT, can't see much smoke at all in fact on WOT, and it's still real cold out here.

The coolant issue has never gotten worse since I bought the car and I've put 30,000 kms on it already. Always had the same exhaust smell, never checked the coolant levels but I flushed the coolant twice and put green stuff in right after I got the car. I would think if it were head bolts it would just leak more and more but nothing's changed.

rca99aurora, I've done all those tests and even the combustion leak test, touted the "best" test is entirely inconclusive. The only symptom listed I am getting is the coolant smell from the exhaust. There is no oil leak to the severity mentioned that I can tell of aside from the "normal" Northstar leak.

[Toronado3800]

Would you say that every 1,000 miles or so you have to ad coolant but not enough that your low coolant light was on? Every 2,000 miles?

I used to do some busy work for a shop where I dispatched tow trucks. If a tire was losing 10 pounds of pressure in 2 weeks I think it was I could usually find the bubbles. Any less often and it just was difficult to find. I am concerned you are chasing a problem for 20,000 miles from now.

[roarr]

toronado3800, I think what I'll do is fill the coolant to the center line, and not add coolant until I get a "low coolant" warning which will likely be at the very least 7-10,000km from now. Certainly nothing to be concerned about, I'm just curious about how that coolant manages to get into the exhaust. Moreso because I want to fix all the issues with the car if/when I sell it.

I just did a few more 0-60, uphill and full throttle runs and you can actually see the temperature gauge moving down as you accelerate, so I'm just going to have to conclude this isn't the head gasket.

I happened to find a thread almost just like this one on another website with the same light blue color in the test fluid, however that user was having other cooling issues (didn't seem like the head gasket but rather a clog of some sort) and there ceased to be any updates to the thread since.

[roarr]

I remember a while back I was getting a hissing noise from the surge tank when I shut off the car. Just bought a new cap, stock 15PSI and it no longer seems to make any noise when the car is hot and shut off. Coolant loss was probably from boiling off through a leak in the cap but I'll find out soon enough. Temps seem to be more stable too. Doubt it'll affect the exhaust smell but who knows, I'll check.

[roarr]

2-month update after the new surge tank cap: No detectable coolant loss when looking into the surge tank, coolant is exactly at the top of the full mark. There might still be a slight leak somewhere but for all intents and purposes, there is no leak. Since the new cap I'd say I put 2,000kms on it, stupid me doesn't keep track of the mileage!

Still get the smell sometimes through the vent and in the engine compartment if I really sniff for it, but it might not be coolant as the washer fluid tube disconnects occasionally (fixed it now) and sprays all over the inside of the engine bay.

[Toronado3800]

May 29, 2015 18:53:30 GMT -6 roarr said:

2-month update after the new surge tank cap: No detectable coolant loss when looking into the surge tank, coolant is exactly at the top of the full mark. There might still be a slight leak somewhere but for all intents and purposes, there is no leak. Since the new cap I'd say I put 2,000kms on it, stupid me doesn't keep track of the mileage!

Still get the smell sometimes through the vent and in the engine compartment if I really sniff for it, but it might not be coolant as the washer fluid tube disconnects occasionally (fixed it now) and sprays all over the inside of the engine bay.

Good deal! Glad to hear your car is running well. Even if it uses metric miles lol. (Metric is better btw, I wish we would just switch)