GQ Overheating dramas - Now cracked head

[grimbo]

Just before Xmas had over heating dramas on my 91 GQ dual fuel. Sorted it out as being a combination of dead water pump and dodgy thermostat. it appeared as if the head gasket was fine, stopped the car before any major over heating.

The GQ has been fine since then with daily driving in city traffic and a couple of trips from Melb tto Mansfield and back.

On the Easter w/End drove to Mildura and around the area no problems. Coming home yesterday noticed the temp guage near the H. Stopped let it cool down, refilled with about 4L od coolant. Drove for abbout 35kms then suddenly upit went again. Stopped let it cool refilled with coolant drove for about 30kms then same thing.

Checked thhe oil and there was no water in it to suggest a head gasket. the car ran fine so I replaced the radiator cap with a brand new one. It seemed to be ok as long as I stayed at about 80-90km/h and 2000 rpm. Any time I had to slow for a town etc and it dropped below 60km/h it would suddenly rise to near the H.

The fan was working as well. I just can't figure out what it might be. Could it be a water pump again or maybe the dual fuel converter or?

Will bbe booking it in to On Track asap but would be interested to here any theories

[GQ Bear]

Having some problems with mine too, only on really hot days or if put a/c on. I've replaced thermostat, radiator cap. water pump, all hoses but still does it.

I always take it out and give it a good clean and flush after every trip, was gonna see about getting cores cleaned, but on closer inspection I think the whole radiator is just Knackered.

Saw a couple on ebay for around $400. A 2 core and a 3 core, is this a good price? and is a 3 core better or too restrictive for airflow

NB. am looking at supercharger in near future

[matthewK]

i took my radiator to a place in braeside to clean up and fix a crack 50 bucks, but in the end i end up going 3 core 290-350 from a joint in dandenong never had a problem since never gets hot

maybe upgrading the radiator is the go?

[fnqcairns]

Grimbo sounds like your new thermostat has died, typical after an overheating event and also typical is faulty one brand new if my exp is anything to go by. Test it with another new one in a saucepan on the stove to near boiling but don't boil. You cannot pay too much for a new thermostat either IMO.

cheers fnq

[mav]

when was the radiator last rodded out by a radiator joint???

[jessie928]

check the engine fan fluid coupling for correct operation and check the radiator for being clugged ( internal and external) it collects HEAPS of shit between the condensor


Jes

[grimbo]

I've got a cracked f$%^&g head. So what needs to be done now. Not happy about paying around the $1500 mark for a new head from Nissan. What other options are there?

[MyGQ]

I had my head crack on me, i had it repaired by Central Coast Engineering for $600 for the crack and a bit more to have LPG valves and shit installed.

[micks troll]

Gday guys i'm just new,but i've had similiar hassels not bad though (88 gq petrol carb) first thing was the temostate ,water pump hoses etc but the biggest drama was if the viscous hub goes, you will soon tell as it will wobble backwards and forward . if it gets too bad the fan will eat the shroud (not good) i fitted a davis craig coupling no probs since a bit pricey tho! mine never got real hot but after wheelin one weekend i went to start the car and snapped the top of no 1 piston out $$$ 5.5k later it was fixed(this was not related to over heating tho). when the motor was recond they recond the radiator and it was 40% blocked yet it didnt over heat as every thing else was replaced. i wish there was easier answers the best bet is start replacing all the older parts before they cause real damage my 2 cents cheers

[Brunsy]

Did my head the week B4 christmas, similar symptoms. I did all the work myself as its not the first one ive done (different vehicle), paid 1700 at ORGERS bayswater, this was a new casting etc ready to go. Honestly speak to them as they do alot of the touring car stuff, just out of interest ask them what they think about welding up TB heads, the owner there Peter has one. I have had no probs since but wouldnt want to either at that price. Hope this christmas is cheaper LOL

[GQ Bear]

I've got a cracked f$%^&g head. So what needs to be done now. Not happy about paying around the $1500 mark for a new head from Nissan. What other options are there?

Is it cracked or gasket blown?
Gasket; remove head yourself, get it surfaced, new valve seals and ports cleaned (around $300), new gasket (around $100), buy a torque wrench (around $120) and put back together yourself. (While you've got it out you could even get about 20thou shaved off for another $50)

Cracked head; remove yorself, see if can be welded(can't always be repaired). Weigh up costs of changeover vs. repair, then reinstall yorself

[bogged]

pay $700-900 for reco on yours, it dies in 12 mths time, that $ to nissan would be cheap.

but understand what ya going thru.

[BowTieGQ]

There is a newer casting from Nissan that is a little thicker where needed. A repair on crack and a full reco for LPG on your head isn't much cheaper than a new one. I'd go the newy and put all valve gear in that. That was my option when mine went but it hadn't cracked. They only crack when they overheat from the head gasket going behind number 6 cylinder. Otherwise try Quikdrive Engineering in Dandy for reco. When I did my pricing when mine shat, Dandy Nissan would do one of the new bare castings for $1100 over the phone, "but I'll check with the boss on Monday and see if we can do better which I'm sure we can". I nearly did that anyway.