Hi guys

Recently bought a 2013 Grand Caravan 3.6. My first Dodge.

When I first got it noted some squeeking coming from what I assumed was the water pump. Checked the coolant level, it had just dropped below minimum, so I topped it back up and noise gone.

Ok, so over the last couple of days the tempurature gauge has been running high. It generally sits at around the 3/4 mark, so above where it should usually be (at half way). But it's been a toucjh random. It would fluctuate quite a bit (almost a quarter) dependning upon braking or accelleration, for example accellerate mildly and it would shoot up a bit, but immediately drop when I came off the pedal a bit - coolantg does not change tempurature that quickly!!

The car seemed fine, just the gauge being odd.

Yesterday (it's very hot here currently) when driving uphill through town it went to full temp on the gauge and the warning light flashed and beeped. Pulled over at the top of the hill, switched it off and went shopping to let it cool a bit.

Came back to the car, checked the coolant level and I swear it was fine. In fact I say it had now gone over the maximum level. HOWEVER, it was in bright sunshine, I did not have my torch and so there is a chance I might be mistaken.

Drove home, went to 3/4 on the gauge again but was fine.

Next morning went to the car expecting to have to suck out some coolant, only to find the reservoir almost empty! Surprised me as I was sure it was overfull the previous evening. But I may have been mistaken!

So, filled it back up to just under the max level and off we went.

Drove a good 2 hours, and seemed to mostly sit at 3/4 on the gauge. Never went higher, no beeps or lights etc.

But later in the same day time to pop out again, checked coolant level and it had virtually all gone. Only a trace in the bottom of the reservoir. So topped it off again, wondering where on earth around 1 litre of coolant has gone in just a few hours. No puddles on the floor!

So set off again, temp gauge shot up to 3/4 in around 2 minutes of driving, which seemed wrong. Then it went to max temp with warning light and beeping.

So, pulled over, checked coolant level - it was empty again! AND could visibly see coolant dripping at a very fast rate from the front right (if sat in car) corner, trickling away down the tarmac.

Assuming possible radiator leak, topped the reservoir up with coolant again and turned around and drove home (7-8 minutes).

On the way home the coolant temp light came on the dash and it was beeping constantly. So eased her towards home with fingers crossed!!

Then something weird happened, the beeping stopped. I looked at the gauage which was on max temp, it had dropped to zero, and the Electronic Throttle Control warning light was illuminated.

Do you think it had gone into some kind of safe mode? To keeps revs low to stop overheating???

Got home safely, checked the coolant level and it had not dropped AT ALL in the 8-9 minutes of driving and the leak etc. As if the coolant in the reservoir could not get to, or was not being sent to, the engine/rad?

Looked under the car, and definitely coolant leak streaks down the lower skirt (black part) under the front bumper. 7 or 8 streaks there, and a slow coolant drip from that corner.

I had expected to arrive home to see all the coolant I put in just a few minutes before gone, remembering that I filled her up before leaving and again at the half way turnaround stage it had used it all! But on the return journey used none.

One thing I did notice is that braking definitely made the max temp reading and warning go off quicker.

I also got home expecting everything to stink of burnt coolant, and maybe see some smoke etc. Seemed ok, surprisingly.

ALL HELP MUCH APPRECIATED!!!

What happening/happened to my car???

 

the vehicle coolant temp should be around 90 to 100*C during normal operation. if your evic has a digital coolant reading monitor it thru the evic.

coolant levels- when the vehicle overheats the coolant expands; it will overflow the surge tank/ reservoir (not sure which you have)...when it cools it will vacuum back into the system. A system with a surge tank can be checked hot or cold. a reservoir system should be checked cold...remove the rad cap and check the level in the radiator as well as the reservoir.

when coolant temp fluctuates so quickly...it could be a sign of air in the system.

I would check that the rad cap is sealing the system. a non sealed system will boil over at normal operating temp. pressurized system increases the coolants boiling point.

put a pressure tester on the cooling system and inspect for leaks.
if no leaks are detected. start the engine and monitor the pressure guage...if it pressurizes fast and the needle fluctuates...it may be a headgasket leak.

make sure the system is completely filled with no air pockets; vacuum filling is the preferred method.

 

Thank you for your advice - very good! I have a pressure tester somewhere for doing cylinders, hopefully that will fit the rad.

Ok, so I have done some more testing on this this afternoon as it was not making a whole lot of sense.

I noted that the bottom right (if sat in the car looking forward) corner of the rad was pretty wet. So definitely had been leaking, as I had witnessed myself when overheated.

So, started the car and let the heat build up. Aftr 10-15 minutes idling it hit max on the temp gauge and warning pinged on. Not long afterward I heard a hissing sound, and indeed a load of collant was coming out from somewhere in the bottom corner of the radiator.

Now, bearing in mind I'm far from an expert on car heating systems, I have a theory - and could you let me know your thoughts on my theory...

Ok, so I'm thinking the thermostat is not operating correctly. So the coolant is inside the rad, but not being distributed through the engine by the thermostat. So the coolant is just sat in the rad, gets hotter and hotter. Do radiators have a pressure release valve? If so, I think that it what is happening when max temp is exceeded...

So, my theory is the thermostat does not open, the coolant in the rad get to max temp, pressure releif valve kicks in and dribbles out a load of coolant, and the radiator draws new coolant back IN from the reservoir, hence using LOADS of coolant constantly.

Does that theory make sense? The top main hose goes from the rad to the thermostat, so if that thermostat does not open the coolant is stuck in the rad. The pipe feeds from the bottom of the reservoir to the opposit top side of the rad. So I'm thinking it's sucking new coolant in to replace the stuff it's spat on the floor at max temp??

Make sense?

 

I’m having a hard time following your descriptions of what’s happening (probably more my fault than yours) but to build on what primem already told you, here’s some more detailed info on proper cooling system operation assuming the level is correct (meaning it’s just below the radiator cap and there’s no air in the system).

As the engine heats up, that heat is transferred to the thermostat through the coolant. When the thermostat reaches the specified temp, it opens to allow flow through the radiator. The water pump circulates coolant through the radiator to allow that heat to be dissipated and the coolant is circulated back through the block and heater core.

The radiator cap serves 2 functions by utilizing what is basically a check valve:

1) It pressurizes the cooling system to a specific PSI. This happens as the engine heats up - that heat causes the coolant to expand and since the cooling system has limited space, the expansion creates pressure which also serves to raise the boiling point of the coolant.

When the expansion exceeds the capacity of the system, the valve in the cap opens to allow the excess to drain into the reservoir.

2) When the engine is shut down and cools off, a vacuum is created. At this point, another valve in the cap opens and allows what was drained into the reservoir to be siphoned back into the cooling system.

One thing I’ve found with late model dodge and Chrysler vehicles is they recommend checking the coolant level when the system is hot (thermostat has opened) rather than cold.

Based on what you’re describing, I think the head gasket is leaking. Engine temp can do some weird things and coolant consumption can make no sense when the head gasket is the problem because the size and location of the leak will have varying effects on correct operation. So, besides pressure testing the system, here are some things to check:

1) With the engine hot, check the relative temperature of the upper and lower radiator hoses by feel. The lower hose should be noticeably cooler than the upper. If the upper hose is hot at all, that indicates the thermostat is opening.

2) When the temperature is fluctuating, turn the heat on full blast and see if heat output in the cabin changes relative to the fluctuations.

3) When the engine is hot, shut it off for about 1 minute, then start it up again and watch for white smoke coming from the exhaust.

Remember- these are just indicators- further diagnosis is needed to verify whether or not the head gasket is the issue.

 

Many thanks for the tips - much appreciated!!!

Ok, so I'm pretty confient it's not the head gasket. There are none of the tell-tale signs, no contamination between coolant and oil, no sluge/cheese in the oil or on the filler cap, no smoke of any kind etc.

To help me understand the process a little more...

So, the water pump pumps the coolant from the engine into the top of the radiator via the large hose, and this goes via the thermostat?

The large lower rad hose puts coolant back into the engine using gravity?

So it goes:

engine > water pump > thermostat > upper rad hose > rad > around rad > lower rad hose > engine

Is this the right order?

I will definitely test the temp of the upper and lower hoses as you suggested. If the thermostat is stuck then coolant is not pumped to the rad via the water pump, and so that hose will be cool?

 

Update, so I checked some online video's and it seems the process is correct:

engine > water pump > thermostat > upper rad hose > rad > around rad > lower rad hose > engine

Now, to simplify my issue I believe I am getting too much pressure build up in the radiator, as if the coolant cannot get out of it.

In the videos I watched they mention that the radiator cap is a pressure release valve, and 'due to high tempurature of coolant [entering the top hose form the engine] there might be chances of of building up high pressure that might block the coolant from entering into the upper tank'


Check out 3:59

And so the radiator cap opens in this instance which sends the coolant to the reservoir.

However, in my case I think the pressure (and temp) continues to build in the rad, as eventually the coolant builds enough pressure to find an outlet. On my rad there is a square plastic thing in the bottom corner, and I think this is where the coolant pours out from when the temp overheats.

Could it be as simple as a faulty radiator cap not releasing the pressure, therefore not allowing coolant into the rad and so overheating???

 

Ok, I apologize for missing this crucial detail that you stated before - that you saw coolant leaking from the bottom right corner of the radiator. I had to re-read your first 2 posts because I didn’t recall seeing it.

I looked at photos of radiators for your van and the drain plug is on the left side of the radiator, so there’s no reason why a normally functioning radiator should have coolant leaking from that corner. The reason the drain plug position matters is that it could’ve been the source of the leak.

There’s a couple of things that are most likely to be the issue:

1) The lower hose is not correctly seated on the nipple for the radiator and/or the hose clamp is not squarely seated on the hose.
2) The hose is dry rotting and/or has been rubbed through by the hose clamp.
3) The radiator is leaking.

Go to a parts store and rent a pressure tester for the cooling system. Clean the radiator (in particular the lower right corner) thoroughly with a garden hose. With the engine cold, pressure test the system and watch the corner. If it doesn’t leak, run the engine to operating temp only (do not let it get hot) then shut it off. Watch the corner for leaks. If you still don’t see any, SLOWLY remove the pressure cap to prevent flash boiling, then pressure test again and watch for leaks.

You should be able to identify the leak with the engine hot or cold using a pressure tester. Just don’t exceed the rating on the cap.

 

OK no problem :-)

Yes, the leak is definitely from the front of the front of the radiator.

The corner is the lower right (if sat in car, offside). If looking from the front of the car it is bottom left of course.

It actually sprayed out a little from that area, spray spots came out of the lower grille and visible on the bumper bottom edges.

In that corner is a square black plastic lug (plug???), which is not present on the other side.

Do these have a drain plug, or do you normally drain by removing the lower hose? If they have a drain plug, do you normally access it from the front via the grille, or the rear?

Thank you!!

 

I don't think it is a hose issue as the leak begins only when max temp exceeded, and then stops again completely once the pressure is released. There is no leak otherwise at all.

 

The only drain plug is on the left side, opposite the lower hose.

If you could see it leaking from the grill area then the radiator is damaged and needs to be replaced. I’d recommend you replace the pressure cap as well if you’re not sure it’s functioning properly as an extra $10-$20 is well worth it to know the cap is good.