My rad over boils buti dnt have a thermostat?

I have a 1.8 kr 16v engine with a top fill rad on, I have a slimline fan on it but I dnt think that's why it's over boilin, I have a 1.5-1.6 engine rad on the car but surely even tho it's not the right rad it wudnt be the reason why it's over boilin if I dnt have a thermostat :/

Anyone have any ideas???

Cheers dan

top fill rads will always spill some water as it gets hot and expands, thats why sensible radiators have an seperate expansion tank

Yeah but it seems to be getting to hot, cuz the temp gauge goes right up ( haven't had it like right to the top of the gauge) but its enough for it to over boil

is the temp sensor ok ? is the fan kicking in ?

Yeah the temp sensor is fine, yeah it kicks in, but just spoke to crazy quiffs n he sed it'll be my fan cuz its a blower not a sucker n it needs to be on the front but am yet to do that but hopefully that'll sort it out

Was the radiator new or secondhand? Topfill radiators are pretty old now...

Nah it's new mate got it from vw heritage

All the fins ok? Undamaged etc? I know I'm just asking the basics, but there's been many other errors in your cooling system setup so far so need to check. By the way, running without a thermostat is a bad idea. A thermostat isn't a 2 way valve, its a 3 way valve. If its cold, it diverts coolant around a bypass channel, if its warm/hot, it diverts it to the radiator. If you remove the thermostat, the water will take the path of least resistance, so about 2/3 of it will go around the bypass and 1/3 of it around the radiator. If it were fitted and open, all the coolant would be going round the radiator circuit.

Also, its undersized, you need to sort this too eventually.

The fans all fine mate cuz it's a brad new fan, it seems to
Kick in when the rad is hot, just one question

If the engine was filled up with coolant without a thermostat (meanin the housing which should have the thermostat is open) would this mean it wud be over filled??? Cuz normally the thermostat wud be closed due to the water being closed I.e not lettin any water passed

Or am I talkin a load of crap??? Lol

I am goin to put a thermostat on it, just didn't realise I never put one on

The correct procedure to add coolant is to add it to fill the expansion tank then run the engine and let it warm up (ie so the thermostat opens) and continue adding the coolant, until there is no more air and the coolant is at the right level.

If you merely added coolant when the engine was cold, then assumed it was full because it was full cold, then there is a possibility of a massive airlock (the entire circuit with the radiator in it, for example) and you'll quickly run into overheating issues.

So no, a thermostat being fitted or not makes no difference to the amount of coolant required, so long as its done properly (save for the tiny volume of the thermostat itself which would have displaced some coolant).

Well I dnt think it wud of been filled up wrong cuzi have it filled up at c q's so pretty sure that wud of be done properly but I will get a thermostat tonight, put it on and fill it back up with coolant n see if that works

Hang on - did you do the work yourself or has the car overheated subsequently to going to a garage eg Crazyquiffs? How is he involved in this? Have you paid for the work?

Nah mate I basically took the car to them n got the to do electrics but I cudnt fill the engine up cuz there was a water housing missing, so I sed to ten to put the housing on then fill it up to get it running but they cudnt get it up to temp cuz the manifold I got I didn't wrap so not really there fault I think

I don't understand the bit about not being able to get it up to temperature because the manifold wasn't wrapped - sounds like a load of rubbish to me.

Was the thermostat fitted or not, when they filled with water? Was it the thermostat housing which was missing? Did they fit this housing, but not the thermostat, then fill the car with coolant?

All sounds a bit dodgy to me.

Nah mate it was a different housing that was missing, I put the thermostat housing on but just didn't know about the thermostat basically, they filled the car up with water ( probably not knowing there alwasnt a thermostat on it,

The bit about the manifold they sed cuz its a 16v stainless steel one, it gets too hot and it's a fire hazard or summat, so I just took there word for it but it sounded about right to me cuz someone on here sed that they are a fire hazard with the steering rack gaitor

But I dunno really I'm just takin other ppls word for it so I dnt really know mate

It pains me to suggest it (because I always favour DIY, for cost and other reasons) but maybe you're best getting the car booked in at CQ to check over the entire conversion and fix any issues.

People say its quick and easy to do a 16V conversion but you really need to do it properly and not cut corners, to avoid unreliability or teething problems. There is an unavoidable requirement to spend time reading up on it and properly understanding things, and money on the required parts.

if the engien is getting too hot without the thermostat then something is wrong with the cooling system, mine never got out of the white zone without one. could be the rad is just too small, a dead waterpump or an airlock somewhere.
plus if you ever have the coolant boil then you will get more airlocks so you have to start the bleeding procedure all over again!

try a new cap to start with, could simply be faulty and preventing the coolant system from pressurising. you are bleeding the system with the heaters set to hot right?

re the fans if you dont run a shroud this will reduce the effectiveness of the fan considerably, so its best to fit one. you can solve the blowing direction by switching the wires over to reverse the fan rotation, or simply swap it to the other side of the fan! the direction wont effect how well it cools the radiator though so dont worry about that.

as a start try bleeding it again:
Run the engine from cold with the cap off and rev it to 2k now and again.  While you are doing this squeeze all the pipes you can get your hands on, and keep the coolant level topped up.  It will eventually start to boil over, at this point turn the engine off.  Once its settled down top it up to the max mark and you should be good to go!

keep an eye on the coolant in the tank to make sure its moving about nicely, if not it could be your waterpump is duff

Firstly I can't do anythin with the heater cuz it doesn't work but hopefully am gettin that sorted on fri

As for the fan I tried swapping the wires round n it dnt do anythin to the rotation, I've put it on the other side of the rad so hopefully that shud be alright

Also what's a "shroud"??

Im gonna get a new cap also cuz the one that's on it is off my other rad so I'll get a new one of those

As for the water pump I'm hoping it works cuz its a brand new one, but I know even new ones cus be faulty, but how can I check to see if the water if moving around the system nicely if I ent got an expansion tank? It's a bit hard to see in the rad

if you look at an oem rad fan you'll see what i mean, it has a metal cowling that covers the whole rad this forces the fan to suck air thru the entire rad not just the smaller surface area around where the fan is. the trouble is you cant put a shroud on the front of the rad that wouldnt be a good idea

when you swap the wires you need to do it on the fan itself it will have a live and earth. take the earth off the battery and put it on the rad temp sensor, and the wire to the temp sensor to the battery earth. if that doesnt work then the fan must have some electrical wizardry inside it

checking the pump without a header tank is a bit tricky as you say, you could take the pump off and check the impeller is intact and not slipping on the shaft i suppose but then you'll have to drain and refill the cooling system again

Right

I swapped the wires round ( the proper ones lol I never swapped the right ones before) n the fan now sucks air, I think I'm gonna make a cowling of sum sort to fit my fan…….. So just a question of the cowling, is there anything I need to take into account I.e do I need to make any extra holes on the cowling for air flow or wud it be ok if it was basically just a plate with the only hole being the fan???

Put a thermostat on it and it heated up a lot quicker than before, but it didn't over boil but I think I might not have the right cap on it so I'm gonna get one of those soon,

Basically the needle on the gauge now goes about 3/4 of the way up and just sits there….. Is that right??