overheating 80series diesil under load

Submitted: Wednesday, Mar 30, 2011 at 21:54

ThreadID: 85326 Views:6965 Replies:14 FollowUps:8

This Thread has been Archived

john y

I have an 80 series 1HZ Cruiser fitted with an after market turbo which on warm to hot days over heats when towing my 5 mtr pop top s/axle caravan,
The vehicle has recently had a new head & gasket fitted a new water pump & radiator hoses new injectors and the diesel pump reconditioned but the problem still persists.The vehicle was also dyno tuned when the head etc was repaired.
The overheating occurs when attempting hills on warm to hot days.
The coolant in the radiator top tank also indicates that the thermostat is allowing the fluid to circulate,the radiator cap has also been replaced.
I don't have an EGT gauge fitted.

Has anyone else experienced similar problems or can suggest a solution to the problem?

Back Expand Un-Read 0 Moderator Share

Reply By: den57 - Wednesday, Mar 30, 2011 at 22:22

Wednesday, Mar 30, 2011 at 22:22

Would check the thermo fan. Toyota sell a 10cc bottle of synthetic oil for them. Had same prob with normally aspirated engine. always overheated on a range but the moment it topped the range you couldnt believe how quick it cooled down. Fluid coupling for fan slips at too low an rpm. Adding the oil worked for 80odd thous k. Then stared to leask and replaced with non genuine unit, new toyota one pretty expensive.

Hope it helps
Den

AnswerID: 449766

Reply By: Wayne's 60 - Wednesday, Mar 30, 2011 at 22:30

Wednesday, Mar 30, 2011 at 22:30

Hi John,

Have you checked the viscous hub on the fan?? It can be a source, and a difficult one to track down, of 80 series overheating. The fan on our 80 is VERY noisy when it kicks in .... and we know that it is working!

Not having a turbo on our vehicle does make it a little difficult to offer qualified advice ................. however .......................

Fit an E.G.T. and drive by the temp readout .............

Check the turbo boost is not OVER boosting ............. a good way to kill the 1hz, which is not a turbo base engine ...... though others have been successful in this direction ........... and on this site!!

If the answers posted on this forum are lacking in informed answers, a search of previous posts may uncover further information ........... or you can sign up to Off Road 80s

or some may suggest the LCOOL Site

Hope you get it sorted ......................... and soon.

Cheers,
Wayne & Sally.

AnswerID: 449769

Follow Up By: Wayne's 60 - Wednesday, Mar 30, 2011 at 22:32

Wednesday, Mar 30, 2011 at 22:32

Oh ...........and it's a diesel .... LOL .......... and you do not indicate the year.

W&S.

FollowupID: 722180

Follow Up By: Member - john y - Wednesday, Mar 30, 2011 at 23:06

Wednesday, Mar 30, 2011 at 23:06

G'Day Wayne

Vehicle is 1997. Viscous fan has been checked and said to be OK. Car has 375000K on clock & has been serviced religiously.Have checked some other sites but have not been able to get any difinitive answers.

Thanks for your interest, JohnY

FollowupID: 722183

Follow Up By: Wayne's 60 - Wednesday, Mar 30, 2011 at 23:14

Wednesday, Mar 30, 2011 at 23:14

Hi John,

No problems and thank you for your reply, I would be checking the turbo boost level and maybe even backing it off a little, the viscous hub is "said to be ok"?? ............ do you hear it running when the temperature rises?? As previously indicated ...... ours is VERY noisy when it is running ........... as in ............ turn the stereo up . LOL.

Hope you manage to sort it out very soon, although cooler winter weather will have a lesser impact ............ summer is not all that far away .......

Cheers,

Wayne & Sally.

FollowupID: 722186

Follow Up By: get outmore - Thursday, Mar 31, 2011 at 07:58

Thursday, Mar 31, 2011 at 07:58

at 375k your viscous hub will almost certainly need attention

im guessing some one just went to turn the fan and felt resistance and said - yep its OK

they are not easy to check properly

FollowupID: 722214

Reply By: Member - Rodney B- Thursday, Mar 31, 2011 at 00:15

Thursday, Mar 31, 2011 at 00:15

Bought an aftermarket thermo fan from Bursons for my 80 series petrol for around $140 . Made a big difference to the temp running and as stated previously you can hear them come in (literally howl on initial engagement)
Have still got the original Toyo hub and will try the satchells in it as well.

AnswerID: 449788

Reply By: Member - Bill S (VIC) - Thursday, Mar 31, 2011 at 00:27

Thursday, Mar 31, 2011 at 00:27

Hi john y,

Could the radiator be too small for an aftermarket turbo and the extra oomph the motor is now putting out?

Bill S.

AnswerID: 449790

Reply By: Member - Phil G (SA) - Thursday, Mar 31, 2011 at 08:06

Thursday, Mar 31, 2011 at 08:06

The way I read it, you haven't mentioned the radiator or thermostat. These were the two main causes of overheating in my daughter's 1997 HZJ80. The radiator top tank was removed and the core found to be 60% blocked (probably because non-genuine coolant had been used previously), and we removed the thermostat and tested it and it was opening 5 degrees too late. Genuine thermostats cost $30 from Toyota. Rodding the radiator and replacing top tank cost us $200.

Also we had a build up of material in the condensor core in front of the radiator that needed to be hosed out. But like yours, our viscous coupling was in perfect condition ( we dismantled it and checked).

BTW, the temp gauges will not move from the middle until the vehicle is about to overheat. They have a built in flat spot so needle sits in the middle between 55 degrees and 95 degrees. Normal operating temp with a TM2 gauge is 76-80 degrees.

Cheers
Phil

AnswerID: 449809

Reply By: WBS - Thursday, Mar 31, 2011 at 08:08

Thursday, Mar 31, 2011 at 08:08

All I can add is that I've got the same set up (model, motor & after market turbo). I do not suffer any overheating problems and never have. I tow a full caravan of 2.5 ton. My turbo runs at 8lb boost. I have fitted an EGT gauge and that displays very interesting results regarding engine temperatures.

WBS

Member
My Profile My Position Send Message

AnswerID: 449810

Reply By: sweetwill - Thursday, Mar 31, 2011 at 08:14

Thursday, Mar 31, 2011 at 08:14

hello John y.
My previous car commodore Ute had the same problem, but soon as it went up a steep incline towing it would over heat after doing all the usual things pump,thermostat, radiator cap,coolant.it still done the same but only on a steep hill, it turned out to be the radiator was 30%blocked with scale when tested, it never over heated after that hope this helps bill.

Billy

Member
My Profile Send Message

AnswerID: 449812

Reply By: Member - Bruce C (NSW) - Thursday, Mar 31, 2011 at 11:01

Thursday, Mar 31, 2011 at 11:01

Hi John Y,

I have a 96 80 series factory turbo. I sort of get the same problem although the engine is not getting as hot as yours.

I have an EGT fitted and the exhaust temp gets to 600 deg. C. which is about 100 deg. C. too many.

Problem comes from over fueling in my case (was working well before rebuild but mechanic has fiddled with adj.) and might be a contributor in your case although you say it has been dyno'ed so I would expect that they would have adjusted the fuel accordingly. Just a thought.

In my opinion, to much black smoke is wasted fuel and does nothing for performance but does a lot to destroy a motor by contaminating the oil more quickly.
If I am wrong on this I would be pleased if someone could enlighten me.

Cheers, Bruce.

At home and at ease on a track that I know not and
restless and lost on a track that I know. HL.

Lifetime Member
My Profile Send Message

AnswerID: 449824

Follow Up By: The Landy - Thursday, Mar 31, 2011 at 11:28

Thursday, Mar 31, 2011 at 11:28

Hi Bruce,

I understand that is correct, too much fuel in a diesel can lead to over-heating, the opposite to a petrol vehicle...

Cheers, The Landy

FollowupID: 722228

Follow Up By: Member - Duncs - Thursday, Mar 31, 2011 at 13:51

Thursday, Mar 31, 2011 at 13:51

That was most definately the problem when my GQ was overheating. I took it to a mob that claimed to fix it, but they did not. It still went like a dog and overheated. Even though my wallet was considerably lighter.

This sent me off on a very expensive wild goose chase. I put a new and bigger radiator in - no difference. I rebuilt the head - no difference. I checked the brakes for drag, repeatedly adjusted wheel bearings looking for drag, all to no avail.

Eventually I took it to a mob in the Souther Highlands, who for some reason don't like to be mentioned here. but they fixed it. The diffeence was unbelievable. As I drove it out of the driveway of the workshop I could tell it was better. The engine was crisp, revs came up quicker, no smoke no matter what I did. I drove home faster than I had driven for a long time, just because I could, and there was no sign of overheating.

The other thing to think about is a boost compensator. It is a diaphragm fitted on the top of the fuel pump to adjust the fuel feed as the turbo boost rises. When I bought the GQ it had an aftermarket turbo and no boost compensator. Set up right they make a huge difference to performance and help save fuel too.

Good luck

Duncs

FollowupID: 722232

Follow Up By: Member - Bruce C (NSW) - Thursday, Mar 31, 2011 at 15:23

Thursday, Mar 31, 2011 at 15:23

Thanks Landy, thanks Duncs.

Confirms what I have been hearing especially your story Duncs.

Cheers, Bruce..

At home and at ease on a track that I know not and
restless and lost on a track that I know. HL.

Lifetime Member
My Profile Send Message

FollowupID: 722243

Reply By: PeterInSa - Thursday, Mar 31, 2011 at 13:40

Thursday, Mar 31, 2011 at 13:40

Had a statesmen with over heating problems, fitted a 5 core radiator and an additional cooler fitted for the auto transmission had helped fix the problem

AnswerID: 449839

Reply By: Member - Wayne B (NSW) - Thursday, Mar 31, 2011 at 16:35

Thursday, Mar 31, 2011 at 16:35

My 1HZ overheated when towing over speeds of 90kph. Temp gauge would read 2mm below red. Never lost any coolant of boiled. I did an 8000kmtrip through the center with it like that.

When I got home I did the thermo fan fluid and checked a few things but I never got to test it towing again as I ended up putting a 1HDT engine in it

Fixed the overheating but I never did find out what was causing the problem with the old engine

WB

AnswerID: 449862

Reply By: Member - Mfewster(SA) - Thursday, Mar 31, 2011 at 17:02

Thursday, Mar 31, 2011 at 17:02

This might be a silly point, if so apologies. Does the viscous coupling also lubricate the fan bearings? If so, don't read further. If not, I'd add a check of the lubrication of the fan bearings to the list.

AnswerID: 449874

Reply By: splits - Thursday, Mar 31, 2011 at 18:29

Thursday, Mar 31, 2011 at 18:29

John

I agree with those who have mentioned the radiator. I remember at TAFE many years ago, the text books listed around 30 reasons for overheating but the teachers said 90% of all cases will be the radiator. After spending 19 years in the industry I would say it is more likely about 98%. If yours is the original then that many years and ks is more than long enough to cause major problems. I would not even waste time and money trying to get it cleaned, just get a new one.

AnswerID: 449890

Follow Up By: trainslux - Friday, Apr 01, 2011 at 15:31

Friday, Apr 01, 2011 at 15:31

As has already been mentioned, ensure clean radiator, both internally, and externally.
The viscous hub on the fan (no the grease does not lubricate the bearings of the water pump, its a grease that gets thicker as it warms, sort of opposite to normal grease).

And

Check fan shrouds, I usually fit that 1/2" self adheisive foam for stopping door leaks between the rad and shrouds to ensure good pull of air thru the core.

And

Check infront of the rad, blocked ac condensor/ lots of stuff on the b bar etc.

The rest has been well and truly covered.

Trains

FollowupID: 722428

Reply By: Gnomey - Saturday, Apr 02, 2011 at 12:16

Saturday, Apr 02, 2011 at 12:16

G'day Johnny
All the usual suspects in an overheating case have been fingered. After a long and frustrating investigation, the source of my overheating 1HZ proved to be a de-laminating main pulley. If you are having any vague problems with keeping batteries charged if might be worth a check.

Cheers
Mark

AnswerID: 450068

Reply By: Member - john y - Tuesday, Apr 05, 2011 at 21:07

Tuesday, Apr 05, 2011 at 21:07

Many thanks to all who replied to my problem.

After Having the head and gasket ,water pump,hoses,cap,injectors replaced and the viscous fan and radiator checked by 4WD "experts" at great cost,the problem persisted,
On advice from an industry source I took the vehicle to a mechanic who has a fine reputation within the 4WD competition community who immediately diagnosed that the rubber elbow on the base of the DTS turbo had degraded and had expanded to nearly double its correct dimensions,under pressure this elbow collapsed and severly restricted the airflow to the engine hence the overheating and overall poor performance. He also found that the viscous fan was not operating properly at higher revs,an addition of additional fluid solved that problem{a problem identified by many respondents].

I suppose that many "experts" within the 4WD industry are in reality self styled and that non technical people like myself are misled by their ads in industry mags.
It was an expensive education

Thanks johny

AnswerID: 450453