Suspect rad is half blocked - only top gets warm

[MisterCruiser]

Can any 90 series owners tell me how long it takes for their cabin to start blowing warm air from a typical cold start?

Also, can ye tell me if after a normal drive, does your entire radiator get warm evenly to touch? Or is it normal for only the top 1/3rd of the rad to be warm and the bottom 2/3rds stone cold under normal light driving conditions. I first noticed my rad being like this about 3 years ago.

I suspect my rad is partially blocked because the bottom 2/3rds seems to be always stone cold (these fins aren't in great condition either) and also because my cabin blows warm air extremely quick, like after 5 mins and less than a mile driving. For a big 3.0L engine I always thought the engine heated up very very quick and blew hot cabin air extremely quick too. Just wondering how this compares to other 90 series cruisers? I reckon it's the original rad. I've a new water pump and thermostat when I done the timing belt a year or 2 ago.

I also have a mk5 Golf 2.0L diesel and it takes about 10/15 mins + 5/6 miles before I start to get warm air, it's easily takes twice or 3 times longer to warm up in comparison to the cruiser.

Is there a way for me to check / test that the rad has full circulation and not half blocked or is checking its entire surface for warmth by hand a sufficient test? I suppose I could disconnect the in and out hoses and flush water through it and see if it comes out the bottom? But any good way to know without removing / draining it? Although, I think I did flush the rad when I changed the thermostat and put new coolant in when I done the timing belt so the rad must have drained out the bottom for me then, I remember opening the plastic drain tap. Maybe it's not completely blocked but not as efficient at letting proper amount of coolant through bottom half and hence bottom doesn't get warm? I had considered renewing the rad when doing the timing belt due to the not so great looking fins from half way down but it wasn't leaking or anything so I left it. Half thinking of replacing it now but just interested in seeing how other rads behave regards fully warm before I replace something that doesn't need replacing.

I gave it an oil service there over christmas and noticed when I switched the engine off with bonnet open I could hear coolant noises, just like typical hissing / pressure noises around the top of the rad and then I could hear drops of coolant in the expansion bottle. I know after a long hot drive coolant will return from the expansion bottle to the rad as the engine sits cooling down, but is it normal for coolant to make it's way into the expansion bottle after just switching off a pretty much cold engine?

I'm trying to keep an eye on it and do some checks now before I start to fear the worst

 

[Shayne]

Remove the radiator for a cleaning now !

Assuming you have a 1kz-te there are thousands of internet pages discussing its tendency to overheat and warp the cylinder head , and just as many thoeries as to why .

Alerted to this by the forum in the early days mine looked pretty good but also learning the temperature gauge is all but useless because it only moves when your into the danger zone i decided to remove it for a clean anyway . I was shocked to find what i can only decribe as a carpet of dog hair very similar to what you will see inside a vacuum cleaner sandwinched between the ac condensor and the radiator especially given as i always dedicated a little time specifically to the rad whenever i had the pressure washer out .

Get it out , wash it , flush the system and while your at it change the thermostat you may as well for cheap piece of mind .

 

[Shayne]

Wait i just read the whole thing and its seems you did most of that so its the heater your more concerned about . I left mine running with the heater blowing hard until it got warm and when it did i could add a few litres more coolant to the rad . So maybe you have air in the system ?

 

[tonytoyota]

Hi Is it manual or auto box if it is auto then it will have a oil cooler in the bottom and if you need a new radiator I have 1 I got for my 90 and have not fitted its £75 if it hopefully.

 

[goodoldboy]

my cabin blows warm air extremely quick, like after 5 mins and less than a mile driving

That sounds about right. The 1KZ TE has a wax pellet type thermostat & this i think makes the difference allowing a quick warm up.

it will have a oil cooler in the bottom

...which won't get warm for a good bit longer if it's an auto. Also the auto box won't go into overdrive or lock up the torque converter (not sure which ?) until it's oil is up to temp.I'm inclined to agree with Shayne ,maybe a bit of an airlock ?

 

[AdventureWagon]

Never used the heater in mine but will try and check the rad next time I'm out. Temp gauge heats up to mid way within 2 or 3km of city driving.

I have an auto but have bypassed the radiator based cooler for an external one. But @goodoldboy is right the trans won't go into lockup until warm plus shift points are slightly delayed.

This is on the petrol 3.4.

 

[MisterCruiser]

That sounds about right. The 1KZ TE has a wax pellet type thermostat & this i think makes the difference allowing a quick warm up.

...which won't get warm for a good bit longer if it's an auto. Also the auto box won't go into overdrive or lock up the torque converter (not sure which ?) until it's oil is up to temp.I'm inclined to agree with Shayne ,maybe a bit of an airlock ?

Thanks for the replies. I've read the threads about head gaskets on here so am aware of this issue and hoping it's not the start of my issue
Mine is a manual. and a 1KZT-E.

I would of thought if I had air in the system surely my heater wouldn't blow hot air at all, or would be blowing luke warm air and not hot.
When I done the timing belt I removed the a/c rad and the a/c pump + pipes etc as the a/c rad was completely disintegrated and turned to dust upon touch so my rad should be getting good air, I also checked the oil in the viscous fan at same time and all was well. I fitted a genuine toyota thermostat, I didn't go for the lower opening stat that I read about some owners here fitting, i just went with the original.

Maybe there's no issue with mine but I always wondered about the bottom 2/3rds of the rad remaining stone cold and I don't remember seeing / hearing the coolant drip back to the expansion tank when I had the bonnet open before.

Thanks for confirming that these cruisers do seem to warm up very quick.
I'd be interested to see if someone could check their rad by hand and let me know if the whole surface area gets warm or if it's like mine with only the top 3rd hot and the rest stone cold, after a normal light drive.

 

[BobMurphy]

As Shane said - there are pages and pages of theories on this (some are mine ).

The thermostat is at the bottom of the engine block so the whole motor has to get hot enough for it to open before you get proper circulation in the radiator. If you are running the cabin heater in cold weather that will cool the motor so you may not get circulation in the radiator under light usage.

It sounds OK to me (but if you intend towing heavy loads I'd fit a 76 degree thermostat - it could save the head).

Bob.

 

[Shayne]

Water is stored in the rad to cool , when the thermostat opens it dumps hot water on top and sucks cold water from the bottom . If it all got warm it couldn't cool your engine and you would be in trouble .

I don't bother much with the heater but the mrs reckons 6 to 8 minutes in the 1kd , 1kz and the 1hd

 

[MisterCruiser]

I drove it on a 100 mile round trip yesterday, mostly motorway at 75mph checked rad by hand when I got there and when returned home, only top 1/4 of rad is hot, rest of rad stone cold and lower hose warm-ish and upper hose hot.

I guess it’s all ok assuming everyone else’s rad does be the same as this after a motorway run.

 

[AdventureWagon]

Tried mine after a 30 min drive through surbubia, top was hot (say 80degC) and bottom was cooler (say 65degC). Not stone cold by any means. Note it is summer here probably about 32 today.

 

[Ciderman]

Just to put your mind at ease, i recently replaced my 80 series radiator for a new unit, completely stock, and also flushed the system prior to that.
With a new thermostat in and new hoses, plus a damn good bleed of the heater circuit - i found that even after a decent hard run, the bottom hose of the radiator is stone cold.
I think its because its a massive cooling system and the thermostat is doing its job of circulating coolant when its required.

Fret not. As long as your coolant is clean, gauge is sitting in the middle and on the level in the header/expansion tank - nowt to worry about.