1HD-T Overheating...Suggestions? (1 Viewer)

[MonsterCruiser]

Aside from the recurring sticking rear caliper issue another recurring problem seems to have surfaced...Back in May I did a day trip where I drove about 900km in a day with mostly highway driving at 90-100km/hr. The highway had some mountain passes, so I slowed down for those. I am running higher boost with a max of about 17-18lbs and I have a post turbo EGT gauge that I keep the readings under 800 F and try to hold a steady max of 750 F or less when the temps get high.

After about 800km the temp started to rise on the temp gauge (stock coolant gauge). It didn't get into the red, but it probably got to about 3/4. I pulled over at the first gas station, and I found that the coolant tank looked like it was bubbling, so I let the truck cool down and then emptied the expansion bottle in the rad and topped up the system. I probably had to add less than a liter of fluid.

I have driven about 4,000km since and I haven't had any issue until this past weekend. I've checked the system periodically, and I haven't had to add any additional coolant to the system. This past weekend I was again on a longer trip, but this time there were more passes and I noticed the temp needle just starting to rise after about 500km, so I stopped at the next available location. Similar to the last time I only had to add less than a liter of coolant and I was on my way.

Coming home I was running the A/C and I noticed it wasn't as cool. I didn't think much of it as none of my temps or temp gauges seemed out of place. I stopped and checked the coolant and it had again come out of the expansion tank. Topped up the coolant and the A/C was back to being nice and cold again. The rest of the trip the A/C was good and the temp gauge didn't rise or anything, but when I stopped at the end coolant had again come out the expansion tank and it was full.

Ok, so now I might looks stupid for doing the same thing over and over again, but I don't seem to be overheating too much, but it's definitely running hot and coolant is being pushed out of the rad into the expansion tank.

I've checked cold, warm and hot and there are no bubbles coming up in the rad with the rad cap off. I don't see any evidence of coolant and oil mixing (I just changed my oil and it was just the usual black). Anyone have any thoughts or suggestions? I'm probably just going to take it to the shop and get them to look at it, but I'm wondering what I'm in for. I'd think with a cracked head or BHG I would see bubbles coming up in the rad, but I don't know for sure. It just seems odd that the only coolant loss I seem to be getting is from coolant being pushed out the rad and out of the expansion tank.

Thanks in advance all!

 

[Douglas S]

Flush the coolant system, then change the t-stat and rad cap. This should be done every few years.

 

[roscoFJ73]

Its somewhat normal for the expansion tank to fill up,thats how it got its name. When the engine cools,vacuum should pull the coolant back into the radiator.
You need a good radiator cap.Yours could be weak and opening at low pressure and this allows the coolant to boil around the bore at a lower temp than when it is fully pressurised,which in turn forces more coolant out.

When the guage is on 3/4 its not exactly overheating.
A good aftermarket temp gauge is a good investment so you know the exact temp.

 

[BCR4619]

X2 on what Douglas has said.... Make sure your rad fins are clean, assuming you dont drive your truck in Mud you should be alright.

When I got my truck when I stuck my finger into the rad there was this red-ish sludge on the inside of the rad, I flushed the system and all has looked good since... check your fan clutch too.... start with the simple things but its odd that it does it one and a blue moon... those are the hard ones to diagnose!

Good luck with your calipers also!

 

[MonsterCruiser]

Thanks guys. I should mention that the coolant was flushed back in October 2012. I can't remember how many kms ago that was but probably 10,000 kms ago, so relatively recently.

I also replaced the rad cap (with OEM) some time in 2013. I think it was only a month or so before the first time the temp rose. This time I thought maybe it was a faulty rad cap, so I bought one at Lordco and I'm still having the same issue, so I don't think the rad cap is the problem. I hope it's as simple as the thermostat. I've also been anxiously watching the kms climb in anticipation of replacing the timing belt and water pump around the 200k kms. Maybe that will get done a bit earlier.

I also realize that the level of the expansion tank will fluctuate, but after sitting for a while the rad still needs a top up. I checked this morning before heading to work, so it was definitely cooled off over night and the rad was low, but maybe I didn't top up enough the day before. After a drive of about 25km today I checked the rad after things had cooled down and it was still at the right level

 

[ForealBoreal]

I think its your rad cap....
If the rad cap doesn't fix it I would check to make sure your water pump isn't pooched.
If thats the case do that and your thermostat for the hell of it.
If that doesn't fix it, time to get your rad redone.

I bet money the rad cap will fix it.

 

[BCR4619]

Lordco is your first problem

I'm sure if you bring it to John he will have a few ideas. But cooling systems are relatively simple for the most part... You can get all the parts for the water pump n timing belt in the US IIRC and it does not take too long to do, this of course if you don't break the oil seal plate like I did, oops

 

[MonsterCruiser]

I think its your rad cap....
If the rad cap doesn't fix it I would check to make sure your water pump isn't pooched.
If thats the case do that and your thermostat for the **** of it.
If that doesn't fix it, time to get your rad redone.

I bet money the rad cap will fix it.

This was my thought too, but I'm still having the same issue with a replacement rad cap.

Lordco is your first problem

LOL...You don't have many options when you are in Grand Forks...

I'm sure if you bring it to John he will have a few ideas. But cooling systems are relatively simple for the most part... You can get all the parts for the water pump n timing belt in the US IIRC and it does not take too long to do, this of course if you don't break the oil seal plate like I did, oops

I did find the "how to" a while back for the 1HD-T timing belt and maybe water pump too, but I just don't have time to work on it. I'm taking it to ATEB on Saturday (unless I have to work ). As long as I don't have a cracked head I'm going to get them to undercoat the truck too. With this brine crap they put on the roads now in the winter I've noticed a fair amount of surface rust starting to show up on the underside.

 

[Adam B]

They're all wrong.

You have the same problem I do - a small crack in the head (or possibly block). ok, I haven't completely ruled out a compromised head gasket but any time I've killed one in the past the symptoms have progressed fairly quickly and left little doubt what the problem was. My money is on the head.

My needle doesn't ever go above the halfway mark - unless it's ~30C outside and I'm doing sustained hard uphill driving. AC on makes it worse, of course, and higher EGTs make it worse. I can baby it a bit and keep it back in the "normal" position for my gauge. This situation has happened once or twice per year under those harsh conditions for several years. I'm calling that normal.

This spring I started noticing the same thing as you - my coolant reservoir was filling up. Not the normal inch of fluctuation. FILLING up and bubbling over. This will only happen on sustained high rpm high boost situations (highway). In my case I am completely certain I have combustion gas entering the coolant, forcing the coolant into the reservoir. The water pump continues to pull liquid from the bottom of the radiator and the engine continues to run at "normal" temperatures. When the radiator gets down about 1L instead of liquid getting forced into the reservoir, air from the top of the radiator is. The process remains at that stage and will continue indefinitely, as far as I can tell.

For peace of mind I still pop the rad cap and pour whatever liquid I can from the reservoir into the rad if I've driven to the interior, before I start the long drive home.

When I get back to the city and do my short drives without sustained high boost and high rpm the system gets a chance to pressurize and depressurize and it eventually pulls all the coolant back into the radiator and fully bleeds itself.

I've pressure tested the cooling system and it tests ok. There seems to be a very, very, very slow leak but according to the test kit it maintains pressure long enough to be considered acceptable. I've replaced the rad cap with no change. T-stat won't cause this. Water pump is fine. Coolant flushed ~50k ago.

 

[Jan-78FJ40]

As has been said, the first thing to check is the rad cap. Original toyota ones are cheap.
Having said that, mine did the same. Small bubbles after a hard drive, pushing out a little fluid, no overheating.
The head was cracked.
Sorry,
cheers,
jan

 

[MonsterCruiser]

Damn...What Adam has written is what I suspected but was hoping wasn't the case because I don't see any air bubbles coming up with the rad cap off. I guess air is only pushed into the coolant under higher boost? In a previous vehicle where the head gasket went the symptoms were more obvious and it would overheat quickly.

If this is the case, I guess the only harm in continuing to drive it is that you might get stranded somewhere? I'll have ATEB do some diagnosing and then go from there. No point in worrying too much until I find out what the actual cause is. Fingers crossed it's something other than a cracked block or head.

 

[roscoFJ73]

I also realize that the level of the expansion tank will fluctuate, but after sitting for a while the rad still needs a top up. I checked this morning before heading to work, so it was definitely cooled off over night and the rad was low, but maybe I didn't top up enough the day before. After a drive of about 25km today I checked the rad after things had cooled down and it was still at the right level

The radiator level is not meant to be right to the top.They should find their own level and should be checked by the level on the expansion tank and topped up there if needed.
If you cant smell coolant ,you are probably not losing any.
If you can ,you should give all your hose clamps half a turn to make sure they are tight.

 

[Adam B]

Well, you'll also know if you're losing coolant because it will be ... well ... disappearing! I know for a fact that I do not have an external leak, and I also don't have an internal leak (coolant getting into the oil or combustion chambers). I have combustion gas getting into the coolant.

Rosco, I can't wrap my head around a radiator with air in it. When the engine heats up and the cooling system pressurizes to the point when the rad cap opens, whatever is at the top of the rad gets pushed out - liquid or gas. When the system cools and pulls vacuum it can only access the liquid at the bottom of the reservoir. After a number of cycles in a leak-free system I can't see how any gas can remain. Every engine I've owned has stabilized with a radiator full of liquid. My 1HD-T did that for the first 6 years I owned it.

In my case, 6 years of normal fluctuation was about 1" in the reservoir. I actually have a line drawn at my normal "hot" level and cold is at the factory "Full" line. It would only go slightly above or below those lines in really extreme conditions (pretty much never).

The minute this problem arose I had a FULL reservoir with coolant coming over the top, but the engine wasn't running abnormally hot. No other symptoms. Only once, I was able to pull over in the middle of a really hard highway run and actually see the reservoir bubbling with the engine still running. I can never duplicate that in the city, even revving it high in neutral with everything hot. Whatever is happening is happening very very slowly and only under high boost, high load, moderately high rpm for a sustained period of time. As I mentioned before, mine stabilizes after it has pushed out about 1L of fluid. Other than that one time I haven't actually had coolant coming over the top of the reservoir. It will rise well above the old "hot" level but to a fixed amount where the system seems to stabilize (can't push out any more liquid because the top part of the rad is full of air!)

 

[roscoFJ73]

Rosco, I can't wrap my head around a radiator with air in it. When the engine heats up and the cooling system pressurizes to the point when the rad cap opens, whatever is at the top of the rad gets pushed out - liquid or gas. When the system cools and pulls vacuum it can only access the liquid at the bottom of the reservoir. After a number of cycles in a leak-free system I can't see how any gas can remain. Every engine I've owned has stabilized with a radiator full of liquid. My 1HD-T did that for the first 6 years I owned it.

!)

So are you saying when you remove the cap,the coolant is right up to the overflow tube?
All 3 of mine have had the coolant about an inch below the overflow tube. All of them would go 2 years between coolant changes without a top up and I took them into some pretty hot places.
If I fill the radiator to the top ,the level always ends up back in the same place.
On warm days the coolant overflow level rises an inch or slightly more.
Im pretty sure the FSM recommends filling the overflow tank to its max level. Then the system finds its own level.
Works perfect for me.

 

[BCR4619]

X2 on what Adam said... Mine is always filled to the top when I take the cap off.

 

[Douglas S]

So are you saying when you remove the cap,the coolant is right up to the overflow tube?
All 3 of mine have had the coolant about an inch below the overflow tube. All of them would go 2 years between coolant changes without a top up and I took them into some pretty hot places.
If I fill the radiator to the top ,the level always ends up back in the same place.
On warm days the coolant overflow level rises an inch or slightly more.
Im pretty sure the FSM recommends filling the overflow tank to its max level. Then the system finds its own level.
Works perfect for me.

This is how mine is as well.

Rad is always full, overflow finds its own level.

 

[veggieguy]

I had a similar problem to yours on my 1HD-T last summer, and it turned out to be the radiator. The fins were corroded and it wasn't cooling properly, especially on longer trips and pulling a load. A new radiator solved the problem. It's hard to check the fins because of the fan and shroud. If you take those off, you could see if the rad fins are corroded and loosening from the tubes. This would confirm whether the rad needs replacement.

 

[MonsterCruiser]

Yup, it could be the rad. It's at the shop now getting checked out.

More info that I didn't post before because my original post was getting long and I wasn't sure if anyone would actually read the whole thing. On my trip back through the interior I did try some things just to get some more situations to tell the shop when I dropped the truck off. I suspected the truck was starting to get hot on the climb west out of Grand Forks. For anyone who had done that drive before you know it's a long uphill climb. I think this is when the A/C started to get warm. After this long climb I had a closer watch on my EGT's and I noticed that they would climb at the normal rate to about 650, but then they increased WAY faster than normal. I tried turning the OD off when I got to about 750 and the EGTs would immediately start to drop and quickly got to about 680 or so.

When I got to Keremeos I topped up the coolant and went on my way. For the rest of the drive back to the coast I didn't let the EGT's go over 650 and I kept boost to a max of 10lbs. Luckily there was lots of traffic, so I actually didn't hold anyone up Near hope the traffic started to crawl. I spent lots of time from Hope to Langley in slow and stop and go traffic. The A/C stayed cold and the factory temp gauge didn't rise at all. However, when I checked the overflow on the ferry it had still spewed coolant out the top and the rad was low.

With the information above the boys at the shop got into a heated debate about whether the problem is actually the fan clutch or the radiator LOL. Either way they don't think it's the head, block or head gasket which gave me some peace of mind, but we'll see what their diagnosis comes up with.

 

[Jan-78FJ40]

There are unfortunately just not many ways for the overflow to spew coolant and the rad becoming low on fluid.
To do so, the system must expand in volume. So air/gas is entering your system somewhere from within (head gasket leak, head crack) or from the outside (bad rad cap, which allows air to be sucked in when the system is cooling down).

Neither your fan clutch nor your radiator (unless it's leaking) can account for the coolant loss and overflow bubbling.

Jan

 

[BCR4619]

There are unfortunately just not many ways for the overflow to spew coolant and the rad becoming low on fluid.
To do so, the system must expand in volume. So air/gas is entering your system somewhere from within (head gasket leak, head crack) or from the outside (bad rad cap, which allows air to be sucked in when the system is cooling down).

Neither your fan clutch nor your radiator (unless it's leaking) can account for the coolant loss and overflow bubbling.

Jan

But if it got too hot due to lack of cooling would it not over pressurize the system and boil so to speak?