overheating mystery

[man on the moon]

So I'm having a minor frustration with the Loyale. It is overheating. I've replaced all the hoses (or they were replaced last summer). I've replaced the radiator cap. I've done a flush and fill. The thermostat works (I think), as the upper rad hose gets HOT once I'm up to operating temp. New radiator last summer. Radiator doesn't seem to have any cool or hot spots, just the expected temperature gradient.

 

It doesn't seem to be as likely to overheat if the temperature is lower (in the 70s), but it still creeps up quite high if I drive long enough. On 100 degree days it gets close to red about 20 minutes after I start driving. Fan is running, etc. Driving on the highway delays the creep-up factor significantly, but still gets there eventually, especially if I slow down below 50 or so.

The only thing I can think of is this: the overflow bottle is missing that little green cap, and most of my problems have started since then. Can that little overflow cap really make that much difference???

I also replaced the horseshoe gasket in the throttle area, but there are no external leaks (there were before). I lose very little fluid, it is small enough amount I can blame the loss on boiling out of the overflow container, but the question is why is it getting that hot to start with?

If it IS that small green cap, well, I'll be a monkey's uncle, I guess, just wanted to inquire to other minds if I need to look at anything else before I make a trip to the junkyard for...a bottle cap.

*ETA: I lost the green cap while doing the gasket replace and coolant flush (was over the course of three days or so last month, and did the hoses at the same time, not sure which factor I screwed up on ).

Edited July 22, 2013 by man on the moon

[Subruise]

smell your coolant....you may have bad hgs

[man on the moon]

My oil looks ok, and I don't have bubbling coolant aside from the random trapped air bubble when I top it off (a cup a week, or so). It's a bit dark, but that could be due to the recent flush and not all the detergent flushing out. Doesn't look oily, to speak of.

What would I be smelling for? It's worth a shot.

[Subruise]

if it smells like fuel or exhaust (ie not sweet, like antifreeze) you may have an issue. did you use a dealer tstat? are you sure your tb seal is working?

[MilesFox]

The radiator may be corroded. Try back flushing it with a garden hose. Observe proper bleeding procedure, especially if your symptoms have arisen after opening up the cooling system.

 

If you ahve a mystery coolant loss, check the little hose under the thermostat between the top of the engine block.

[man on the moon]

I checked (and replaced) the little hose off the back of the intake. New hose between the heater core pipe and water pump. Both rad hoses new last summer, and a new radiator. I just remembered there is a vent hose at the thermostat, but there is no sign of a leak there, I could replace that hose too, though. I'd forgotten about that one.

Pretty sure the TB gasket is holding, no sign of drippage or spray, I even stand and watch it while the motor is at temp, because I've had hoses and gaskets leak, but dry up before I can spot them. I see no sign of leakage inside the TB either. Coolant is cloudy but I'm 99% sure it's a little bit of leftover detergent (it isn't bubbly, just cloudy

I flushed and backflushed the radiator through both hose connections. The heater core. Did the motor flush from both heater lines and the water pump. I bled the system, and check it regularly.

I'll smell the coolant in the morning. Oil looked good last time I checked a few days ago (this has been going on a few weeks now).

I'm off Thursday, so I'll unplug the coil from the disty and plug in my pressure gauge to each cylinder, see if I have any leaks. If it isn't that or the hose I forgot, I'm going to really be miffed. At that point I think I'd take it in and have Shawn check it out with equipment I don't own.

Edited July 23, 2013 by man on the moon

[MilesFox]

a bad intake can ingest coolant if you are smelling it out the tail pipe. It will simulate a bad HG but without loss of compression or coolant in the oil.

[man on the moon]

I like the point you make about the intake, that  matches my symptoms much more closely, and could explain the lack of leakage on top of the motor and inside the TB (due to recent gasket replacement) if the leak is to the inside of the intake.

 

Aside from sniffing the exhaust, is there anything I can do to check for it? I can pull the valve covers pretty easy.

[man on the moon]

Actually, the intake manifold gaskets were new last summer, too. Could be those, but I wonder if I shouldn't check the TB gasket again (or re-install???). I'll smell the exhaust regardless, and whatever else was recommended above (writing them down). This better not get me, or I'll be unhappy.

[man on the moon]

Sniffed the exhaust today, no obvious coolant smell. Will do some more poking tomorrow and see where it takes me.

[Dwayne Oxford]

Take it to someone who's got a combustion gas (CO2) detector. https://www.youtube.com/watch?v=1_SIwHMLmkM

[man on the moon]

I poked a little further today, with a flashlight. The thermostat bypass hose I had forgotten about (with it being completely BURIED under stuff) has a little buildup around the motor end, mostly on the flat surface of the block. I'll replace that in the morning, thanks to an exceptionally good parts guy at O'reillys. Thanks awesome parts guy . I now have TWO parts stores I enjoy visiting, at least as long as he's still there.

 

If it still has issues, I have reached my capacity in terms of equipment and would have to take it to someone who can do either a tailpipe test, or a pressure test, or an emission gas chemical color changey test.

[man on the moon]

I swapped out the thermostat bypass hose a day or two ago. In direct sun, stop-and-go traffic, and hot (90+ degrees), it still got way warm; however, yesterday was overcast and it stayed closer to where it should be. And coming home after dark it stays just below the middle, which is awesome. I think I'll check the hose clamps and adjust/tighten a bit.

 

I may still take it in for a test or two, but it's most of the way to solved.

That said, I do feel like a bit of an idiot. "Where are my glasses?!?"..."They're on top of your head!"..."Oh..."

Thanks for all the ideas and prompting me to check things I missed. I'll holler either way if I need more or if it's all good.

[letank]

As you said that increased speed delays the overheating, more air more cooling.... this is my guess:

if turning the heater to full heat dropped your temp gauge a tad, I would suspect that the radiator is in need of a rodding... plugged w
tartar built up. You could try a chemical flush with one of those prestone for neglected radiator flush chemicals.

We expect your temp gauge to be correct... one of those infrared thermometer should help you... and should show a good 30 to 50 F degrees difference between the upper and lower radiator hose... depending on outside temp.

[man on the moon]

Well today sucked. The last few days it's been running warm while hot, but dead-middle in the shade or at night, which is awesome. Then today I had to run across town, and on the way back it spiked up into the red.

 

Water pump, or something else? I don't see any leakage except out of the overflow reservoir. No bubbles, oil looks good, exhaust seems ok to me. Radiator hoses are getting warm.

 

Does the water pump have a clutch, or is it driven by the belt directly? It was a new radiator last summer, but I suppose it could fill up with crud...though I've flushed and backflushed and water flows readily through it.

[man on the moon]

I suppose this would be a good spot to mention that though it is a Loyale, the motor is an EA81. Hoses and such are identical or similar, but I don't know about the water pump.

[scoobiedubie]

Loose cylinder head bolts will cause overheating.  Look on the underside of the radiator cap for any kind of deposit.  Look in the overflow bottom for the same deposit.  The deposit is from the cylinder head gaskets.  Tighten all cylinder bolts as required by simply removing the camtower covers and the oil lubricating crossbar, and use 3/8" x 17mm socket.

 

Lack of an auxiliary fan and/or lack of a good radiator thermostat that triggers the auxiliary fan, and/or lack of power to the auxiliary fan and/or lack of a good connection to the radiator thermostat, will cause over heating.

 

Running headlights, radio, etc requires more alternator electricity, which may then cause extra strain on the engine that triggers higher temps.

 

A mouse nest in front of the radiator will cause overheating.

[man on the moon]

I checked the oil cap and the dipstick. Both are good. The overflow tank is good. Exhaust has no distinct coolant smell. Watching it run with the cap off and there are no bubbles to speak of in the radiator. No obvious signs of leakage and all new hoses. New radiator cap. Even with the overheat and boilover today I might have added two, possibly three cups--and a lot of that was just gushing (not bubbling) out of the overflow tank when I lifted the hood.

It's been running warm, but not as badly as it had been once I replaced that last hose the other day. Could be the intake gaskets, I doubt it's the heads. At least as the initial cause, today's overheat could have triggered head problems that will crop up in the future. However, the intake gaskets were new last summer, and my exhaust has no smoke (even cold) and no apparent smell while running. If it is that, the diagnostic characteristics were not discernable to me. Keep in mind minimal loss of coolant.

 

Waterflows well through the radiator, though it could be partially plugged. Water in one side and it gushes out the other hose (rad set flat, and the water shoots out the other side).

 

Just hope this overheat didn't set me up for more problems...

Edited August 4, 2013 by man on the moon

[TomRhere]

I would swap in another T-stat, just cause.

 

It could be cause of your issue.

[JuhaKankkunen]

Hi!!! You can also check if fans are running in the correct direction. I saw a car in which someone changed the radiator, trying to do so, cut the cables fan and the assembled incorrect way. Check that.

[man on the moon]

The fan has not been moved since last summer, and has not previously caused problems. This is a new problem. I will install a new t-stat, though the radiator and hoses get hot and do have a gradient--could be insufficent flow just using the 3/8" bypass I suppose.

Edited August 4, 2013 by man on the moon

[scoobiedubie]

When it is running hot, and the engine is still on,  have you popped the hood and specifically seen the auxiliary fan, that sits on the passenger side of the vehicle, spinning?  You use the word fan, but it is not clear which of the two fans that you are referring to.  And it is not clear that you have two fans that are functioning properly.

[man on the moon]

Yes, the electric fan blows. The car has an EA81 motor in it, so there is no clutch fan. The electric fan is wired to a switch and I run it anytime the car is on. It has not been a problem until the last two weeks or so, most dramatically yesterday.

Last summer the intake manifold gaskets were new, along with a new radiator and new rad hoses. Since then I've replaced all the hoses (even the one I forgot initially). New throttle body gasket. New radiator cap.

 

Flush and re-fill this month. Radiator has good flow. Fan works. Everything was fine until the middle/end of June or so. Exhaust and coolant both smell and look normal to me.

 

I will pull the thermostat out tomorrow and see how it runs without, that way I can be certain a new one did/didn't fail out of the box.

Does the water pump have a clutch or is it a solid shaft driving it? Or perhaps the impellers are worn? I don't want to pull it off until I've checked the 'stat, but it is on my mind.

[NorthWet]

The waterpump is rock-simple; unlikely to be an issue unless it is leaking or obviously broken.  Belt driven, no clutch.  Speaking of belts, what condition is your belt in?  Reasonably new, not glazed or cracked, decently tensioned?  A slipping belt might not be noticed at speed; I have had this happen on belts on other makes.  (This tends to cause an issue at speed rather than while driving slow or idling.)

 

How do you have the heater hoses set up?  I am not sure what is the proper way to plumb them on an EA81 in an EA82 body.  This might make a difference.

[man on the moon]

The lower heater hose is identical to the EA82 hose, the water pump is in the same location and the pipe runs off it at the same angle. The upper hose required a flexible hose, but has plenty of flow, no sharp corners, lots of volume. The thermostat has a little different angle and position, making the fitted hose not fit quite right, but the flexi-hose does well. ShawnW put it together for me last summer. If necessary, I will take it back again, but I like to rule out the stupid stuff before I fall back to paying someone to tell me something I should have known the first time .

 

(I like your work Shawn, don't worry, just being independent before I bother you with simple stupid things).

 

Good to know on the water pump. I'll pick up another belt too, though the one on the motor at present doesn't seem glazed at all, and I'm not having any trouble with the alternator/battery/spark/lights/etc. It's cheap enough and will need to be done at some point anyway. May as well toss it on the pile if I can afford it!

 

ETA: I reversed the hoses in my mind, let me make the correction: The UPPER hose is identical between the two motors. The thermostat is in the same position relative to the radiator. The LOWER hose requires a flexi-hose as the water pump comes off at a slightly different angle and position.

Edited August 7, 2013 by man on the moon