Overheating

[Mr. Adventure]

I'll try to be concise.

89 4wd is overheating. I have done work on it including
TPS
Flush Coolant
new wires plugs cap air filter but none of that applies to this

On the Maiden Voyage I was going up to the mountains, it was in the high 80's- low 90's. About half way up I saw the needle creep to 3/4 line, I pulled over and idled for a bit and it brought the temp back down once up into the cooler climate the temp stayed fine.

Once I got the O/D working I loaded up for vacation, A kayak on the roof and another inside with me. It was 105, and I climbed up a pretty steep mountain, the temp went up to a bit above 3/4 on the way up but coasting down it went back to normal. When I got off the freeway and on the street everytime I would stop it would creep up and continue up. Eventually it got pretty high and I pulled over and when I shut it off it boiled out of the over flow a whole mess of liquid. Once it quit over flowing I filled it back up with water, got on the freeway and made the rest of the 80 miles no problem even having to do stop and go traffic for a bit.

Then down in San Diego on one hot day in traffic I got the temp gauge going up and it wouldn't go back down by idling. When I pulled up to our house it lost a bit of coolant from the over flow, but not the whole thing. Added more water and it was cool for the rest of the trip.

Then on the way home I had two kayaks on the roof and it was at night about 82 or so. I saw the temp go up over hills and drop back down a bit on the other side but 80 miles into the trip I was running a bit less than 3/4 and I pulled over and it went red when I got to the parking lot. I shut it off and it over flowed A LOT. I had dinner then filled it back up with A LOT of water and made it home no over heating issues.

I figured I must have blown the head gasket with a small leak and it was loosing water through the overflow and eventually it would just boil over. So after hearing how much a HG replacement would cost me I ordered a test kit online. While waiting for it to ship I found an amazing deal on a JDM import 3Y with only 30,000 original miles. It was such a good price and I was so sure it was the head gasket I snatched the engine up.

I get the tester in the mail and I just did it (Letting the engine warm up to operating temp) Hooked it up to the radiator cap and bubbled air through the liquid and it never turned yellow! I had it hooked up for about two minutes and it stayed blue the whole time until after a bit it sucked in some of the radiator fluid, but two minutes is what it said to leave it hooked up for and it stayed blue the whole time.

So what could it be, Fan Clutch or Radiator right? Fan clutch feels the same resistance as the one on my JDM engine so I think it's alright. How would I check the radiator? any ideas? thanks!

[Mr. Adventure]

I changed the radiator cap and burped the system then added some head gasket sealent just incase.

I know that's a lousy solution but I has this clean 3Y I'll put in I just need the engine to last me a month or so So I can get stuff together around here then change the engine

[llamavan]

Maybe I missed it reading too fast, but did you change the t-stat, using a genuine Toyota t-stat?

What you are experiencing sounds EXACTLY like a super-small HG breech. You are finding it in performance because you're pushing the van really hard (stuff on roof, high ambient temps); you may be able to drive the van "around town" for ages without knowing there's a problem. A HG tester may not pick up exhaust gasses in the coolant unless you FIRST run the van hard enough to spew out the overflow but NOT so much that when it cools (like, cools enough to remove the rad cap safely!) that it drains the overflow tank letting outside air into the equation. Guess how I learned this ...

I know you are really excited about that low-miles 3Y, but 3Y engine + 4WD van, especially 4WD A/T van is a recipe for having a totally gutless paperweight that you can't sell for anything close to what you just put into it. I do not exaggerate; we keep seeing this happen. Your best bet is to buy a genuine Toyota HG (er, "valve grind gasket") kit and get 'er done. Get a refund on the 3Y OR sell it to some weirdo* who still runs and loves his/her 3Y van (that's assuming the 3Y you bought is EFI, not carburated, a whole 'nuther potential problem with these "30K" 3Y engines).

Gwen

* I get to say this 'cuz I'm one of 'em.

[Mr. Adventure]

Well I put that gasket sealant in there because I figured if it's a head gasket crack it's really tiny and it seems to have done the trick. Been driving it around (freeway 40 miles or so) in 100 degree weather and have lost no coolant.

Ill change the coolant and add another bottle of that stuff so it will fill in any more ruptures get some more life out of the engine.

Is the 3Y really that under powered in a 4wd? I had a 3Y auto and I never lacked for power (I have a samurai too and the 3Y is way more peppy). If so I guess I either sell the EFI 3Y to someone with a older van they want to get a lot of life out of or I could look for a older 5speed. A 5 speed with a locked rear axle would work pretty well for towing and light off roaring right?

[llamavan]

There's two schools of thought on the sealant. One is that it works (and it certainly does sometimes). One is that it also seals up things like the rad passages and small coolant passages in the block. FWIW. I would think twice before adding more since you have it behaving acceptably now.

I absolutely wouldn't put a 3Y into ANY 4WD van, stick or auto.

The 3Y I'm happiest with is in a totally stripped down 2WD 5sp cargo van. At that point — now nearly 1000lbs lighter than a stock 4Y 4WD 5sp — the 3Y 2WD performance becomes comparable to the 4Y 4WD. When I say "comparable" I do not mean equal — each is better at some things and worse at others, so which is "best" depends on what matters to me at the time. The stripped 3Y van has faster enough acceleration to deal with city drivers and better mileage in stop-and-go driving, but climbing long freeway-speed grades is a perpetual slow-down, sometimes winding up driving in 3rd gear in the far right lane or even on the shoulder. My 3Y cargo van is pretty happy hauling a llama (puts +/- 300lbs right over the rear wheels), but grumbles noticeably if there's someone in the passenger seat. My 4Y 4WD doesn't even notice a person in the passenger seat.

A really good idea would be to ask around and locate anyone with first-hand experience running a 4WD with a 3Y engine; also search this forum and others (toyotavanpeople.com and yotavans.org) for people who've tried it.

Good luck,

Gwen

[Mr. Adventure]

I dunno in my old 3Y we'd load it down with 11 people and cruise the freeway fine.

My 4x4 van with the overheating issue we loaded 10 people into it and drove freeway speeds up hill to the beach and it was cool. But I stick to the slow lanes driving. I'm not concerned with going faster than 65 and don't expect to up a steep incline

[bushcat]

Maybe I missed it reading too fast, but did you change the t-stat, using a genuine Toyota t-stat?

What you are experiencing sounds EXACTLY like a super-small HG breech. You are finding it in performance because you're pushing the van really hard (stuff on roof, high ambient temps); you may be able to drive the van "around town" for ages without knowing there's a problem. A HG tester may not pick up exhaust gasses in the coolant unless you FIRST run the van hard enough to spew out the overflow but NOT so much that when it cools (like, cools enough to remove the rad cap safely!) that it drains the overflow tank letting outside air into the equation. Guess how I learned this ...

I know you are really excited about that low-miles 3Y, but 3Y engine + 4WD van, especially 4WD A/T van is a recipe for having a totally gutless paperweight that you can't sell for anything close to what you just put into it. I do not exaggerate; we keep seeing this happen. Your best bet is to buy a genuine Toyota HG (er, "valve grind gasket") kit and get 'er done. Get a refund on the 3Y OR sell it to some weirdo* who still runs and loves his/her 3Y van (that's assuming the 3Y you bought is EFI, not carburated, a whole 'nuther potential problem with these "30K" 3Y engines).

Gwen

* I get to say this 'cuz I'm one of 'em.

I think this could be what I'm experiencing. I can drive it around town fine, it idles ok and will only get up to 181 if I just let it sit there and run. I've replaced the fan clutch, water pump, thermostat. When I hop on the freeway now, it runs fine for a while then starts to heat up and then boil out the coolant overflow reservoir. I tried to do the HG tester as mentioned above but no color change and I couldn't get the car hot enough while idling to really get it hot. Debating whether to get the head gasket replaced and hope that it fixes the problem. I'm in a dilemma because I've replaced so much already yet is there going to be another similar repair in the future after this?

1. Car doesn't overheat while idling, car overheats and coolant bubbles out the overflow when driving highway speeds in heat.
2. HG tester doesn't pick up exhaust in coolant, maybe because it's not getting hot enough.
3. Debating whether I should take it to a shop for a HG job. I've already put a new clutch, water pump, transmission rebuild, fan clutch, and thermostat.

[bikeregg]

It seems you have replaced everything in the coolant system except for the heater core and the radiator. One or both of these parts could be partially plugged, reducing the efficiency.

Get a pressure tester for the cooling system. It has various caps that fit different radiators and you pressurize with a hand pump. Pressure should remain steady. If you lose pressure, you have a leak and are losing cooling efficiency.

It is hard to do in our vans, but you can test the radiator for cool spots. Remove the seat pan and fan shroud. Start the engine and warm it up. Keeping clear of the fan, touch all over the radiator looking for cool spots. It should be warm/hot all over the cooling fins. Cool spots indicate plugged passages. Replace or recore the radiator.

Do you get heat? The heater core also has a function in cooling the engine. If you don't get adequate cabin heat from the heater core, it might be plugged and need replacement.

Good luck.

[bushcat]

Had the shop pressurize the cooling system and inspect for leaks and then do a hydrocarbon test. They said it's 100% accurate. No coolants leaks but found hydrocarbons in the coolant of about 100 parts per million. I'm not smoking out the back or anything. I also tried one of those head tests you get off amazon with the fluid that changes colors and that didn't work for me. Debating on paying someone 1500 for a head gasket job.

[bikeregg]

Had the shop pressurize the cooling system and inspect for leaks and then do a hydrocarbon test. They said it's 100% accurate. No coolants leaks but found hydrocarbons in the coolant of about 100 parts per million. I'm not smoking out the back or anything. I also tried one of those head tests you get off amazon with the fluid that changes colors and that didn't work for me. Debating on paying someone 1500 for a head gasket job.


As long as there is no coolant in the oil and no visible oil in the coolant, I wouldn't worry about microscopic hydrocarbons being present in the coolant. There are many reasons they might be present.

I'd still check the radiator for cool spots.

[Gambit]

Are you losing coolant other than it flowing into (or out of) the overflow - if you drive around town for a tank of gas, do you need to top it off? Does it suck back into the system after the overflow has filled and the van cools?

And the obvious question - assuming you tried a new radiator cap?

[bushcat]

Just wanted to update this thread and say that it seems the head gasket was the issue. Although not detectable in one of those test your head kits from Amazon with the fluid, test at the shop for hydro carbons in the coolant and they were rising as the engine heated up. No smoke out of the tailpipe. Had mechanic replace head gasket with toyota head gasket. Drove it home on a drive that would have overheated the van in the previous condition and it stayed 185 and under.